The functional analysis of the 15th century fortification of the Grodno castle

Radosław Biel

doi:10.37190/arc210403

Abstract

The aim of the article is to discuss the potential purpose, and then a functional analysis of the structure, the stone relics of which were discovered during the archaeological research conducted in 2018 and 2019, on the zwinger of the Grodno castle, located in Zagórze Śląskie. The chronology of the structure, based on the analysis of the accompanying artefacts, was established in the first half of the 15th century, linking its destruction with the Hussite wars that were going on at that time. The analysis of the iconographic material and the results of research carried out on similar sites in Silesia, the Czech Republic and Moravia allowed for a hypothesis that the structure in question was a relic of a so called parkan – the oldest, previously unknown line of additional fortifications. Such wooden or stone-and-wooden objects would be the first response to the firearms spreading at that time. The theoretical model of the effectiveness of this type of fortification is considered, taking into account a number of basic factors, such as the terrain, the possibilities of armaments at that time, and the location of attackers and defenders. Various scenarios are discussed, taking into consideration the results of practical and theoretical experiments related to the use of early modern firearms and artillery published in the literature on the subject. The results of the conducted analyses seem to confirm both the proposed function of the structure and a number of benefits of its construction.

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2021

4(68)

DOI: 10.37190/arc210403

Radosław Biel*

The functional analysis of the 15

century fortification

of the Grodno Castle

Introduction

Relics of a previously unknown stone structure dis-

covered on the zwinger of the Grodno Castle, located in

Zagórze Śląskie (Wałbrzych district), were discovered for

the rst time in 2017. The archaeological research con-

ducted in 2017 was aimed at establishing the chronology

and structure of the earthen embankment located on the

castle’s zwinger

. The article aims to describe discovered

relics and their potential function, as well as to present the

results of the functional analysis of the application of such

a solution in the Grodno Castle.

The discovered relics of the stone structure were sub-

jected to photographic and drawing documentation and

the photogrammetric Structure-from-Motion method were

used to create 3D model. In this way, a documentation

for the purposes of further analyses was obtained. The re-

search reports are in the Archives of the Regional Oce

for Monuments Protection in Wałbrzych [1]–[3]. Further

analysis aimed at interpreting the discovery was carried

out on the basis of the methods traditionally used in hu-

manistic descriptive studies of architectural theory accord-

ing to the classication proposed by Elżbieta Niezabitow-

ska [4]. Studies of written and iconographic sources were

undertaken, the literature of the subject was familiarized

and comparative analyses were carried out. The assump-

tions and results of analogous experiments published as

part of works on the theory of military and defence were

ORCID: 0000-0002-1505-1279. Institute of Environmental Bio-

logy, Wrocław University of Environmental and Life Sciences, e-mail:

radoslaw.biel@upwr.edu.pl

Due to the content of other articles contained in this issue of “Ar -

chi tectus”, the historical outline of the Grodno Castle and a detailed

description of the course of these studies and analyses of the artefacts

will be omitted.

used

to create a simplied model of the hypothetical ef-

fectiveness of the supposed parkan (outer defensive wall

with wooden construction) from the Grodno Castle.

Characteristics of the discovery

The relics of the structure were found in the north-east-

ern part of trench No. 6 (Fig. 1). Its coping was located

at a depth of about 2 m from the rst oset of the upper

castle’s walls captured in the same research trench [2].

Later in the work, this fragment of the wall is referred to

as the northern section. It crossed the trench transversely

along the south-west and north-east axis, running paral-

lel to the wall of the upper castle, approximately 6.5 m

from it. At that time, due to the discovery of the papal bull

of Avignon obedience Pope Benedict XIII (made in the

course of the same research), initially little attention was

paid to the discovered stone construction. Only as a result

of architectural consultations conducted by Małgorzata

Cho rowska, more attention was paid to the exposed struc-

ture relics.

In order to capture the further layout of the object, dis-

covered in 2017 at a length of only 2 m, another survey

trench was established to the south of it in 2018 [3]. It was

marked out at a slight angle in the relation to the previous

one, so that its northern border was approximately 2 to

0.69 m away. The initial, too ambitious research area in

trench No. 7 was quickly reduced during the works, as

a result of which the southern section of the structure was

nally fully exposed at a length of 1.2 m. At this point, it

turned at an angle of about 25° to the south, thus no longer

The author of this text, an archaeologist and architectural historian

by profession, some details of the technical aspects of the functioning of

rearms consulted with Łukasz Andrasiak, a second lieutenant in the

Polish Army.

30 Radosław Biel

system, no object contacts that could be associated with

a possible foundation trench were observed. The stones

were placed directly on the natural rock wear layer with-

out being buried (JS 7008 and 6008) (Fig. 3). In the case

of the tested sections, no remains, or even negatives, of

any wooden elements were found.

The entire structure was covered with a layer of black

clay humus with numerous burns, brick fragments, slopes,

charcoal and a large amount of artefacts (Fig. 3)

. As in

most archaeological sites, the stratigraphic units (JS 7005

and JS 6004) were interpreted as remnants of war dam-

age [3]. Based on the dating of nds within these layers,

the moment of destruction was widely established for the

century. The connection of the hypothetical moment

of the structure destruction with the Hussite siege seems

obvious, especially taking into account the discovered

military equipment. In this particular case, they could be

related to the Hussite raid in 1429 described in the work of

Robert Weber [5], but unfortunately, he does not provide

the source of this information.

A detailed analysis of the archaeological nds is presented in this

issue of “Architectus” in the article describing the results of archaeo lo-

gical research conducted in years 2017–2019.

running parallel to the wall of the upper ward, but rather

slightly heading towards it (Fig. 1).

Both the northern and the southern sections of the struc-

ture were made of medium-sized at stones, 0.2 to 0.4 m

wide. Only one larger-size erratic boulder, which was part

of the northern section, was observed. The stones were

placed in a careless manner and connected with mostly

etched clay mortar of dark orange colour. The southern

section consisted of approximately 4 rows of stones and

its average width was approximately 1 m, and the north-

ern section – 3 rows, ranging from 0.6 to 0.9 m wide. Ad-

ditionally, on the eastern side of the southern section, i.e.,

inside the fortications, additional numerous stones were

discovered, the arrangement of which seemed chaotic.

They were in no way bound to the actual wall and were

interpreted as destroyed (Fig. 2).

In the northern section, the number of stones at the foot

of the structure was much smaller. It is possible, however,

that this is the result of mistakes made during the explo-

ration and removal of some of them

. In the stratigraphic

Before the nature of the structure was recognized, its material had

been partially displaced during the excavation work.

Fig. 1. Research trenches, along with the planar orthomosaic

of the discovered relics of structure in trenches No. 6 and 7

and its hypothetical course in the section between them

(elaborated by R. Biel)

Il. 1. Lokalizacja sondaży badawczych wraz z ortofotomapą

reliktów konstrukcji odkrytych w sondażach 6 i 7

i jej hipotetycznym przebiegiem na odcinku pomiędzy nimi

(oprac. R. Biel)

Fig. 2. Horizontal plan of the trench No. 7 with the orthomosaic

of the southern section of the so called parkan

(elaborated by R. Biel)

Il. 2. Plan poziomy sondażu 7 z ortofotomapą

południowego odcinka parkanu (oprac. R. Biel)

The functional analysis of the 15

century fortification of the Grodno Castle 31

Assuming that the exposed wall was only the founda-

tion for a larger stone and wooden structure, and taking

into account its location and the proposed dating, it is pos-

sible that, as a result of the carried out excavations, the

remains of the oldest, so far unknown to the science line

of the fortications of a specic form, were discovered,

which in the literature are referred to as so called parkans

[6]–[8]. Their genesis is closely related to the transition

period between medieval and modern siege techniques.

Parkans in castellology

The dynamics of development and changes caused by

the introduction of rearms resulted in hastily imple mented

modernizations, which did not always lead to the forma-

tion of completed forms [8]. In Silesia and Bohemia, this

development is visible primarily during the Hussite Wars,

during which traditional medieval fortications were not

able to withstand attacks with small arms and cannons.

To prevent direct access and the possibility of easy ring

shots towards the main walls of the castle, the construc-

tion of clay embankments, sometimes with stone facing,

or stone foundations with wooden structures erected onto

them [7], [9]–[11]. In this way, the zwinger space (be-

tween outer and inner castle’s defensive walls) was ob-

tained, limited, on the one hand, by internal walls, and

on the other, by a bulwark. This solution not only made

it dicult to break through the perimeter of the forti-

cations, but also allowed for the placement of two rows

of shooters. What is more, it ensured smooth movement

for the defenders [7]. The structures created in this way,

in the literature referred to as parkans, constitute a spe-

cic evolution of the previously used fences or palisades.

Various forms of wood were used for their construction

– poles, logs or planks, and placing them on foundations

prolonged their durability. The fact that the stone founda-

tions were not bonded with mortar made them tougher in

absorbing the power of shots red in their direc tion [12].

At the same time, fences should be distinguished from

wooden, earth and stone fortications registered on old-

er transitional type castles, known both from Polish ter-

ritories (e.g. Pieszyce-Rościszów, Bukówka, Rościszów,

Wałbrzych – Stary Książ) [10], [13], [14] and Czechia

(Angerbach u Kožlan, Hlavačov u Rakovníka, Tachov,

Týnec nad Sázavou) [15]. One important issue, which is

the problematic nature of the used term “parkan”, should

be mentioned here. In Polish and Czech scientic litera-

ture, the use of this word can be understood in two ways.

Some researchers, when using it, mean zwinger [6], [7],

[16], [17], and others mean palisades, fences or walls [8],

[13], [14], [18]–[20]. As the purpose of the article is not

to solve the problem of terminological correctness, it was

concluded that the “parkan” was the fortications forming

the outer line of defence.

If, as a result of later transformations, the rst exam-

ples of modernization of medieval fortication systems

had been destroyed, researchers very rarely had the op-

portunity to register them in the eld [11], [21]. Most of

the archaeologically researched remains of this type, re-

lated to the Hussite wars, are known from the territory of

Czechia (Most, Starý Žeberk, Nový Žeberk, Albrechtice,

Oheb, Lipnice, Orlík near Humpolec, Křivoklát, Švihov,

Košťálov [9], [12], [13], [18], [19])

. The main dicul-

ty in reconstructing the potential appearance of fences

erected with dierent materials was the fact that stone

was mainly used to build foundations. Therefore, their

wooden superstructures remain mostly a mystery to re-

searchers (Fig. 4). However, the later iconographic rep-

resentations (Fig. 5), such as those included in the man-

uscript Codex Palatinus germanicus [22], provide some

clue. They show both simple palisade structures and

wooden superstructures with numerous arrow slits, with

Some of the mentioned objects are described in this issue of

“Architectus” by Milan Sýkora.

Fig. 3. Stratigraphy with the orthomosaic of the southwestern section of the trench No. 6 (elaborated by R. Biel)

Il. 3. Stratygrafia wraz z ortofotomapą południowo-wschodniego profilu sondażu 6 (oprac. R. Biel)

32 Radosław Biel

sidewalks or even covered with roofs. Based on them, as

well as on the results of archaeological research, in re-

constructions and visualizations, parkans are most often

presented in the form of simple palisades erected on em-

bankments or stone foundations (Most, Volfštejn, Nový

Žeberk or Šoštýn) [7], [19], [23]. More technologically

advanced structures serving as positions and shelters for

defenders (e.g., Kalich, Panna, Rýzmburk near Oseka)

are suggested much less frequently [7], [12], [18]. For

example, the researchers of the Kalich castle proposed

not only a parkan surrounding the entire castle, but also

additional one creating a corridor leading to the forward

defence point [12].

All the construction method, location and the proposed

dating of the relics discovered at Grodno Castle seem to

correspond to similar objects. However, how eective

could an additional line of fortications be in a form of

just a palisade built on a stone foundation?

Theoretical effectiveness

of the Grodno Castle’s parkan

In order to carry out a functional analysis of the hypo-

thetical fence, a simplied model was created, in which

the basic factors inuencing the possibility of ring under

ideal conditions were taken into account, such as: terrain,

building method, possible location of attack points, ap-

propriate location of all these elements in relation to each

other and the technical possibilities of armaments from

that time [24]. However, the incorporation of specialized

data into the model, such as the ballistic values of indi-

vidual types of weapons and missiles, was impossible due

to the insucient number of experiments carried out for

weapons from that period. Although it can be assumed

that, even in spite of generalizations and simplications,

Fig. 4. Variants of reconstruction of so called parkans discovered at sites in Czechia (elaborated by I. Lehký, source: [18])

Il. 4. Propozycje rekonstrukcji parkanów odkrywanych na stanowiskach na terenie Czech (oprac. I. Lehký, źródło: [18])

Fig. 5. Hussite army besieging the Hohengeroldseck Castle in 1486.

Illustration from Codex Palatinus germanicus

(source: [22])

Il. 5. Oblężenie przez wojska husyckie zamku Hohengeroldseck

w 1486 r.

Ilustracja z Codex Palatinus germanicus

(źródło: [22])

The functional analysis of the 15

century fortification of the Grodno Castle 33

hook guns, which are usually referred in sources under one

term such as “puszka” [25]. As these were not the times of

mass production, the then rearms were not standardized,

so the examples referred to by the same name had dier-

ent sizes, structures and widths of the barrels (Fig. 6). It is

visible in the discovered artefacts gathered in the museum

collections

. Apart from them, he most frequently used

ranged weapons should be mentioned, i.e. crossbows, and

the constantly used barobalistic weapon – trebuchets. Also

in the case of artillery weapons, their diversity is re latively

large. The basic type were bombards, divided into smaller

eld guns and larger siege guns, called howitzers.

Except

for them, there were also tarasnices intended for direct

re, which with time, together with hook guns, were used

to defend walls [25].

The practical signicance of the above-mentioned

types of ranged and artillery weapons is a subject of con-

stant discussion by theoreticians and practitioners of mil-

itary art. The range of distances given not only in sources

but also in scientic studies is extremely divergent [24],

[28]–[30]. Certainly, an important factor was the indivi-

dual characteristics of each specimen which inuenced

The largest collection of small arms from this period is available

to visitors to the Museum of Western Bohemia in Pilsen.

the presented model allows to obtain answers regarding

the potential benets resulting from the application of ad-

ditional fortications.

The technique of assaulting permanent resistance

points by the Hussite troops diered not only depending

on the besieged object but also the type of carried out op-

erations [25]. Signicant dierences can be noticed in the

approach of the siege of castles and towns in Bohemia

and Moravia, and objects lying on the way of the Hussite

raids. In the case of the former, the time did not play a sig-

nicant role [26]. In addition to the most frequently used

re of varying intensity, aimed at destroying and creating

a breach in the walls, trenches were also made under the

walls. In extreme cases the besieging troops built forti-

cation systems with towers and stockyards surround-

ing the attacked object with a tight blockade [17], [25].

One of the best-studied places in terms of identifying this

type of siege is Lichnice Castle. Archaeological research

conducted in its vicinity provided evidence of such ac-

tivities, and the reconstructed line of siege forces ran in

the distance between 300 and 400 m from the castle [27].

However, in the case of the raids conducted in the years

1428–1433, the main strength was the element of surprise

resulting from the exceptional mobility of the Hussite

troops. These assaults were carried out only when de-

fences could be taken in stride, given the speed which the

troops were moving with, and too well-protected points of

resistance were then ignored. It can only be assumed that

each attempt was associated with the calculation of the

success chances, and for this purpose all available means

and weapons were used [25].

Equipment of the 15

century troops

Much information about the existing rearms at that

point can be obtained not only from written and icono-

graphic sources but also from archaeological nds [25].

While the development of rearms in individual armies

was irregular and it is impossible to present it in detail

in a short article, in the light of the available data on the

Grodno Castle and the political situation that prevailed in

the 15

century, this analysis can be without any doubts

narrowed down to Hussite troops. It is true that the de-

fenders of the castle themselves were most likely not

Hussites, but there are no grounds for assuming glaring

technological disproportions in the armaments between

the various sides of the conict.

The main part of the Hussite troops during larger plun-

dering expeditions was the infantry [26]. As a rule, there

were ten footmen for one horseman. Although today it

is impossible to determine exactly what the division of

weapons between individual units looked like,

it is known

what types of weapons were used. And so, among melee

weapons, ails and spears with hooks were in the lead, with

the use of swords, cords, glaives, maces, axes, pickaxes,

as well as stabbing weapons known from archaeological

research – rondel daggers and daggers. When addressing

the issue of rearms, which is the key to considerations

regarding the functioning of the parkan, it

should be noted

that the most common written sources mention pistols and

Fig. 6. The Armory of the Museum of West Bohemia in Pilzno

with numerous examples of early modern firearms

(photo by R. Biel, 2017)

Il. 6. Zbrojownia Muzeum Zachodnich Czech w Pilźnie

z licznymi egzemplarzami wczesnonowożytnej broni palnej

(fot. R. Biel, 2017)

34 Radosław Biel

their capabilities. Additional information on this subject

is provided by reconstructive experiments [31], [32]. For

the purposes of the presented model, underestimated, av-

eraged and hypothetical values were adopted, as a result

of which the range of individual types of weapons could

correspond to the ranges presented in the Table 1. Trebu-

chets were excluded from this list because they were us-

ing plunging re and any strengthening would not protect

against them under any conditions [33].

As a part of the conrmation of similar weapon types

use in other armies during this period, the so-called sig-

nature registers of the Kingdom of Poland can be briey

mentioned

[35]. Thanks to these documents containing

a list of soldiers and their equipment at the time of join-

ing the service, we obtained the most information on the

development of this type of armament for the lands of the

Kingdom of Poland. These documents were the basis for

determining the amount of the payout or possible com-

pensation. The registers mention three types of rearms

known from the Hussite troops, that is: hook guns, pistols

and hand cannons [35].

Parkan’s characteristics

For the wall of the upper castle, the assumed height

was 15 m and the thickness was 3 m (Fig. 7b). Probably,

as presented in Chorowska’s article, it was lower in this

particular place, but even raising it and making it equal to

the other, better-preserved fragments do not signicantly

aect the results of the analyses. The biggest unknown

is the structure of the parkan itself. The analyses only

conrmed the initial assumptions that the height of the

Kazimierz Górski introduced the registers to a wider audience at

the end of the 19

century and to this day they remain the most com pre-

hensive and easily accessible publication on this subject [34].

palisade was proportional to its defensive values. For the

purposes of the publication, an arbitrary height of 4 m was

assumed, which, taking into account the construction pos-

sibilities at the time and the results of comparative anal-

yses, seemed to be an appropriate obstacle at the same

time, but also did not require too much work during con-

struction.

The method of calculations

The terrain model and its prole have been developed

assuming that it has not changed signicantly over the last

500 years. From the downloaded les in the .LAS format,

measurements classied as terrain were extracted, and

then a numerical model of the terrain and a vertical AB

cross-section with a length of a little over 500 m were

created. Point A was marked in the place of the outer face

of the upper castle wall, and point B in the area of today’s

center of Zagórze Śląskie (Fig. 7a). At the same time, the

height of the terrain at that time was taken into account,

which the researchers managed to document in the trench

No. 6, in troducing an amendment to the obtained AB

cross-section on the studied section. The attackers were

positioned at 3 hypothetical points C, D and E, which

were determined based on the terrain in combination with

the values presented in Table 1. Thus, the absolute shot

distance at point C was approximately 30 m, for point

D it was approximately 50 m, and for point E – 500 m

(Fig. 7a), which would suit people using the hook gun,

tarasnica and bombard.

The ballistic values of each type of weapon have been

simplied to a minimum. For points C and D, due to the

relatively small distance, the shooters’ eld of view is

shown, not the possible ight paths of the missiles. In the

case of point E, theoretical ballistic curves were calculat-

ed using the following formula derived from the equations

for motion and velocity:

where:

g – gravitational acceleration (9.81 m/s

α – angle at which the projectile was red,

– projectile muzzle velocity,

h – initial height of the projectile,

x – distance (on the Earth’s surface) travelled by the

projectile at a given moment,

y – height of the projectile at the moment.

And so, based on the research carried out for the Mons

Meg bombard, the muzzle velocity was initially assumed

at 315 m/s, the initial height as 0 m, the analysed distance

was 500 m, and the target heights ranged from 72.65 to

88.43 m, which corresponded to the outer face of the cas-

tle wall.

The spatial data needed for this purpose was obtained from the

resources made available free of charge by the Head Oce of Geodesy

and Cartography.

Table 1. Hypothetical, averaged values of the effective range

and the maximum range of different ranged weapons and artillery

used at the turn of the Middle Ages and Early Modern Period

(elaborated by R. Biel)

Tabela 1. Hipotetyczne, uśrednione wartości donośności skutecznej

oraz maksymalnego zasięgu różnych rodzajów broni dystansowej

oraz artylerii wykorzystywanych na przełomie

średniowiecza i nowożytności (oprac. R. Biel)

Type of the weapon

Effective killing

range [m]

Maximum range

[m]

Crossbow 30 500

Pistal 20 150

Hook gun 30 300

Tarasnica 100 300

Howitzer 150 350

Bombard (heavy) 500 1700

hx gx













tan

cos



The functional analysis of the 15

century fortification of the Grodno Castle 35

Results and discussion

In the case of the attackers from both points C and D,

it seems that the additional fortications did not constitute

any obstacle in ring shots at the defenders located on

the castle walls (Figs. 7b and 6c). At least hypothetically

at one point, the defenders were able to re their shots

unaected by the attackers’ response for a short moment,

but after crossing it, the attackers entered the blind zone

– both they and the defenders were unable to re (Fig. 7b).

In the case of a greater height of the fortications, the po-

tential of preventing direct shots at the same time reduced

the defence capabilities. On the other hand, with lowering

the height, the width of the dead zone would decrease pro-

portionally, while the total height of 2 m, with the appro-

priate skills of the defenders, would allow at least theoret-

ical making it null. At the same time, attackers with such

a height of fortications should not be able to raise their

weapons high enough, and certainly not to re a precise

shot. In the analysed model, the parkan completely pre-

vents direct re on the lower part of the walls from points

C (Fig. 7b) and D (Fig. 7c), so in their case its eective-

ness seems indisputable.

It seems that the fence fortications would be the big-

gest obstacle in the direct attack on the wall. Regardless

of its height, overcoming an additional obstacle was tan-

tamount to direct exposure to re from the defenders, with

the simultaneous lack of the response possibility. This

made it impossible to approach the wall and make the ex-

cavations mentioned in the written records, although in

the case of Grodno Castle it was also ensured by the solid

rock itself on which the castle was built.

The last considered aspect is the bombardment from

point E (Fig. 7d). Although it might seem that the issue

of ring from point E will require deeper considerations,

as a result of carrying out a series of calculations with

variables in various congurations, it turned out that also

here the additional reinforcements completely full their

role. With a distance of 500 m and a muzzle velocity of

315 m/s, hitting the castle wall, even without this obstacle,

seems to be a real feat. It would have been possible only

if the angle of the shot had been within a narrow range

between 8.5° and 11.4°. At the analysed distance, only

a signicant reduction in speed and a directly proportional

change in the angle of inclination would have aected the

projectile’s ight path. The feat of ring a shot to bypass

the fence with the proverbial lob which would have re-

sulted in a direct shot at the lower parts of the walls was

not only almost impossible, but also completely point-

less. Even if medieval artillerymen would have managed,

Fig. 7. A hypothetical model of three scenarios of attack on of the Grodno Castle along the line of the parkan:

a) the course of the designated AB cross-section of the terrain along with individual attack points marked on the topographic map,

b) point C located on the closest road running approx. 30 m from the wall of the upper castle,

c) point D located on the lower path, approx. 50 m from the wall of the upper castle,

d) point E, located approx. 500 m from the castle in the center of today’s Zagórze Śląskie (elaborated by R. Biel)

Il. 7. Hipotetyczny model trzech scenariuszy ataku i ostrzału zamku Grodno na linii parkanu:

a) przebieg wyznaczonego przekroju terenu AB wraz z zaznaczonymi na mapie topograficznej poszczególnymi punktami ataku,

b) punkt C znajdujący się na najbliżej położonej drodze przebiegającej ok. 30 m od muru zamku górnego,

c) punkt D zlokalizowany na niżej położonej ścieżce odległej ok. 50 m od muru zamku górnego,

d) punkt E usytuowany ok. 500 m od zamku na terenie centrum dzisiejszego Zagórza Śląskiego (oprac. R. Biel)

36 Radosław Biel

against all logic, to re a cannonball exactly at an angle of

45° with an exact speed of 75.8 m/s, it would have been

tantamount to donating these bullets as a gift and replen-

ishing the ammunition of the castle crew. In this way,

an additional obstacle in the form of a simple wooden pal-

isade, if it had not stopped the enemy missiles completely,

it would have certainly reduced their speed, and thus the

damage caused. But was even a projectile red at a 10°

angle at 315 m/s, after ying 500 m and still keeping it at

312.64 m/s, a threat to 3 m thick stone walls?

Despite the fact that written records usually agree on

the damage caused by red cannonballs

, material sourc-

es contradict them. The marks on walls, and sometimes

even cannonballs discovered in the castle walls like the

ones in castle Rýzmburk near Osek, suggest that the bom-

bardment was not as devastating as the chronicles suggest.

For obvious reasons, the number of practical experiments

that would allow this myth to be conrmed or debunked

is very small. The few experiments, in which the power of

historic artillery have been tested, rely on the use of repli-

cas of guns from later centuries. The most information on

the possibilities of 15

century bombards is provided in

the publication from 2016 [32], in which theoretical con-

siderations were subjected to computer simulation. And

although the case of one of the largest bombards of the pe-

riod known to us was analyzed – Mons Meg, and the cal-

culations themselves were simplied for the needs of the

computing power, nally even the possibility of punching

a brick wall with a thickness of 1 m was questionable.

Based on this experiment, a possibility of piercing a 3 m

thick stone wall bonded with lime mortar can be rejected.

Therefore, not believing the historical records, it should

be assumed that, although not so destructive, still eective

ring from medieval bombardments focused on the grad-

ual straining of the stability of the castle walls. Only the

development of artillery caused an arms race and the pro-

Usually they were supposed to pierce the castle walls and

destroy everything completely, injuring people at the same time. An

example story about the siege of the Scottish castle Threave mentions

the punching through the castle wall by a bullet red from the bombard

Mons Meg, and then tearing o Margaret Douglas’s hand, who was to

eat inside the object [32].

gress of fortication thought, which in the case of defence

points was associated with the modernization or abandon-

ment of such a function. In this situation, the existence

of an additional obstacle, which would be constituted by

even the simplest parkan structure, seems to be entirely

justied by practical reasons. At least in the presented

model, it prevented direct re on the lower parts of the

wall

, and even penetration of cannonballs through the

wooden superstructure probably resulted in a signicant

decrease in their kinetic energy.

Conclusions

In the light of the presented data, the stone structure

discovered during the archaeological research of the

zwinger at the Grodno Castle may be a foundations of the

previously unknown stage of the castle fortications mod-

ernization. The connection of the fact of their destruction

with the date of the Hussite raid in 1429 is conrmed by

the chronology of covering it layers and discovered ar-

chaeological nds. Analogous parkans known predomi-

nantly from castles in the former Kingdom of Bohemia

provide some suggestions as to the likely appearance, but

at this stage of research it is impossible to present its full

reconstruction. The functional analysis showed that even

in the case of the simplest form of a palisade, it could full

its basic tasks. Most likely, they were the impediment to

direct access to the proper castle walls and the impedi-

ment to direct artillery re. Determining the layout of the

newly discovered line of fortications and possible clar-

ication of the method of its construction at this moment

seems possible only in the case of subsequent excavation

research. This discovery is a novelty in the history of the

construction development of the Grodno Castle, and at

the same time ts into the development of the fortication

thought known from the surrounding lands.

Translated by

Kinga Janowska

The structural violation of the wall at its base would lead to the

fastest possible breach.

References

[1] Konczewski P., Biel R., Sprawozdanie z poszukiwań i badań arche-

ologicznych na Zamku Grodno w Zagórzu Śląskim, gmina Walim,

Wrocław 2017 [manuscript in: Archiwum Delegatury Wojewódz-

kiego Urzędu Ochrony Zabytków, Wałbrzych].

[2] Konczewski P., Biel R., Sprawozdanie z badań archeologicznych

na międzymurzu Zamku Grodno w Zagórzu Śląskim, Wrocław 2018

[manuscript in: Archiwum Delegatury Wojewódzkiego Urzędu

Ochrony Zabytków, Wałbrzych].

[3] Konczewski P., Biel R., Sprawozdanie z badań archeologicznych na

Zamku Grodno w Zagórzu Śląskim, Wrocław 2019 [manuscript in:

Archiwum Delegatury Wojewódzkiego Urzędu Ochrony Zabytków,

Wałbrzych].

[4] Niezabitowska E.D., Metody i techniki badawcze w architekturze,

Wydawnictwo Politechniki Śląskiej, Gliwice 2014.

[5] Weber R., Schlesische Schlösser, Bd. 2, Meisenbach Riarth &

Co., Dresden–Breslau 1910.

[6] Menclová D., České hrady, 2. díl, Odeon, Praha 1972.

[7] Durdík T., Ilustrovaná encyklopedie českých hradů, Libri, Praha

2009.

[8] Bogdanowski J., Sztuka obronna, Zarząd Zespołu Jurajskich Par-

ków Krajobrazowych w Krakowie, Kraków 1993.

[9] Sýkora M., Veselý H., Povrchové archeologické průzkumy vybra

ných českých hradů z doby husitských válek, Hrady Českého stře do-

hoří, Ústav archeologické památkové péče severozápadních Čech,

Třebenice–Most 2014.

[10]

Jaworski K., Wały kamiennodrewnianoziemne jako element for 

tykacji późnośredniowiecznych zamków sudeckich, [in:] K. Wa chow-

ski (red.), Kultura średniowiecznego Śląska i Czech, Uni wer sytet

The functional analysis of the 15

century fortification of the Grodno Castle 37

Wrocławski, Centrum Bada Śląskoznawczych i Bohe mistycznych,

Wrocław 1996, 85–92.

[11] Guerquin B., Zamki w Polsce, Arkady, Warszawa 1984.

[12] Kalich a Panna. Hrady Jana Žižky, I. Lehký, M. Sýkora (edd.),

ÚAPPSZČ, Most 2016.

[13] Boguszewicz A., Corona Silesiae. Zamki Piastów fürstenberskich

na południowym pograniczu księstwa jaworskiego, świdnickiego

i ziębickiego do połowy XIV wieku, Wydział Nauk Historycznych

i Pedagogicznych Uniwersytetu Wrocławskiego, Wrocław 2010.

[14] Legut-Pintal M., Rajski P., Podobne czy niepodobne – uwagi na

marginesie analizy formalnej obiektów obronnych na podsta wie

numerycznych modeli terenu. Przykład grodów i zamków z umoc

nie niami drewnianoziemnymi na Śląsku, Polska, “Architectus”

2019, nr 1(57), 21–38, doi: 10.5277/arc190102.

[15] Durdík T., Hrady pechodného typu v Čechách, Agentura Pankrác,

Praha 2007.

[16] Doležalová K., Vyhodnocení archeologických nálezů z areálu

obléhacího stanoviště v trati Ohrada u hradu Lichnice Magisterská

diplomová práce, Masarykova Univerzita, Brno 2012.

[17] Sedláček A., Hrady, zámky a tvrze království Českého, Díl 12:

Čáslavsko, Argo, Praha 1900.

[18] Pyšná sídla mocných. Hrady a tvrze na Mostecku, I. Lehký, M. Sý -

kora (edd.), ÚAPPSZČ, Most 2014.

[19] Sýkora M., Hrady doby husitské, Diploma thesis at the Faculty of

Philosophy of Charles University, Most 2013.

[20] Chorowska M., Dudziak T., Jaworski K., Kwaśniewski A., Zamki

i dwory obronne w Sudetach, t. 2: Księstwo jaworskie, Instytut Ar-

cheologii Uniwersytetu Wrocławskiego, Wrocław 2009.

[21] Guerquin B., Zamki śląskie, Wydawnictwo Budownictwo i Ar-

chitektura, Warszawa 1957.

[22] Mönch P., Codex Palatinus germanicus, Heidelberg 1496, Univer-

sitätsbibliothek Heidelberg, https://digi.ub.uni-heidelberg.de/diglit/

cpg16 [accessed: 15.11.2021].

[23] Vlček P., Ilustrovaná encyklopedie českých zámků, Libri, Praha

2001.

[24] Krenn P., Kalaus P., Hall B.S., Material Culture and Military His-

tory: Test-Firing Early Modern Small Arms, “Material Culture Re-

view” 1995, No. 42(1), 21–38.

[25] Ziółkowski K., Husyckie wojska polne. Kształt i organizacja armii,

PhD thesis, UAM, Pozna, 2015.

[26] Durdík J., Husitské vojenství, Naše vojsko, Praha 1954.

[27] Teplý J., Obležení hradu Lichnice 1428–1429. Dnešní stav stop

po obléhacím okruhu, [in:] M. Drda, Z. Vybíral (edd.) Jan Žižka

z Trocnova a husitské vojenství v evropských dějinách: VI mezi ná

rodní husitologické sympozium, Tábor 12–14 íjna 2004, Hu sit ské

muzeum v Táboř, Tábor 2007, 463–489.

[28] Górski K., Historya artyleryi polskiej, Wende E. i Spółka, Warsza-

wa 1902.

[29] Andrade T., The Gunpowder Age: China, Military Innovation, and

the Rise of the West in World History, Princeton University Press,

Columbia 2016.

[30] Idzik J., Ołowiany grad: zarys historii rozwoju artylerii do czasów

przednapoleońskich, “Annales Universitatis Paedagogicae Cra-

coviensis Studia de Securitate” 2018, Folia 257, nr 8, 35–53, doi:

10.24917/20820917.8.3.

[31] Chlebowicz P., Ręczna broń palna w średniowieczu. Badania ek-

sperymentalne, Certus, Toru 2013.

[32] Lewtas I., McAlister R., Wallis A., Woodley C., Cullis I., The bal-

listic performance of the bombard Mons Meg, “Defence Techno-

logy” 2016, Vol. 12, Iss. 2, 59–68, doi: 10.1016/j.dt.2015.12.001.

[33] Jurga R., Machiny wojenne, Donjon/Pelta, Warszawa 1995.

[34] Górski K., Historya piechoty polskiej, Księgarnia Spółka Wydawni-

cza Polska, Kraków 1893.

[35] Grabarczyk T., Ręczna broń palna w świetle rejestrów popisowych

piechoty zaciężnej z lat 1471–1500, “Acta Universitatis Lodzien-

sis. Folia Historica” 1999, Vol. 64, 27–48.

Abstract

The functional analysis of the 15

century fortication of the Grodno castle

The aim of the article is to discuss the potential purpose, and then a functional analysis of the structure, the stone relics of which were discovered

during the archaeological research conducted in 2018 and 2019, on the zwinger of the Grodno Castle, located in Zagórze Śląskie. The chronology of

the structure, based on the analysis of the accompanying artefacts, was established in the rst half of the 15

century, linking its destruction with the

Hussite wars that were going on at that time. The analysis of the iconographic material and the results of research carried out on similar sites in Sile-

sia, the Czech Republic and Moravia allowed for a hypothesis that the structure in question was a relic of a so called parkan – the oldest, previously

unknown line of additional fortications. Such wooden or stone-and-wooden objects would be the rst response to the rearms spreading at that time.

The theoretical model of the eectiveness of this type of fortication is considered, taking into account a number of basic factors, such as the terrain,

the possibilities of armaments at that time, and the location of attackers and defenders. Various scenarios are discussed, taking into consideration the

results of practical and theoretical experiments related to the use of early modern rearms and artillery published in the literature on the subject. The

results of the conducted analyses seem to conrm both the proposed function of the structure and a number of benets of its construction.

Key words: Middle Ages, castellology, Hussite Wars, Silesia, Grodno Castle

Streszczenie

Analiza funkcjonalna XV-wiecznego parkanu na zamku Grodno

Celem artykułu jest omówienie potencjalnego przeznaczenia, a następnie analiza funkcjonalna konstrukcji, której kamienne relikty odkryto

w trakcie bada archeologicznych prowadzonych w 2018 i 2019 r. na międzymurzu zamku Grodno, położonym w Zagórzu Śląskim. Chronologię

konstrukcji, w oparciu o analizę towarzyszącego mu zabytkowego materiału ruchomego, ustalono na 1. połowę XV w., wiążąc jej zniszczenie z trwa-

jącymi wówczas wojnami husyckimi. Analiza materiału ikonogracznego i wyników bada prowadzonych na analogicznych obiektach na Śląsku,

w Czechach i na Morawach pozwoliła na wysunięcie hipotezy, wedle której omawiana konstrukcja stanowiła relikt parkanu – najstarszej, nieznanej

dotąd linii dodatkowych umocnie. Tego typu drewniane lub kamienno-drewniane obiekty miałyby stanowić pierwszą odpowiedź na rozpowszech-

niającą się wówczas bro palną. Rozpatrywany jest teoretyczny model skuteczności tego typu umocnie, biorący pod uwagę wiele podstawowych

czynników, takich jak ukształtowanie terenu, możliwości ówczesnego uzbrojenia oraz lokalizacja stanowisk atakujących i obroców. W dyskusji

omawiane są różne scenariusze, uwzględniające publikowane w literaturze przedmiotu wyniki eksperymentów praktycznych i teoretycznych związa-

nych z wykorzystaniem wczesnonowożytnej broni palnej i artylerii. Wyniki przeprowadzonych analiz wydają się potwierdzać zarówno proponowaną

funkcję konstrukcji, jak i szereg korzyści płynących z jej budowy.

Słowa kluczowe: średniowiecze, kastellologia, wojny husyckie, Śląsk, zamek Grodno

Zagórze Śląskie, Grodno Castle.

The eastern wing of the upper castle

from the 2

half of the 16

century,

from the side of the courtyard

(photo by A. Gryglewska, 2021)

Zagórze Śląskie, zamek Grodno.

Wschodnie skrzydło górnego zamku

z 2. połowy XVI w. od strony dziedzica

(fot. A. Gryglewska, 2021)