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Sieges in Medieval Warfare

the First and Fourth Crusade

Korean Minjok Leadership Academy
International Program
Kim, Hyun Kyu
Term Paper, AP European History Class, October 2007

Table of Contents

I. Introduction
II. The Selection of Cases
III. Elements of Successful Sieges
III.1 Synopsis
III.2 Complete Blockade
III.3 Reinforcements
III.4 Constant Attack on the Walls
III.5 Morale
III.6 Treachery
IV. The First Crusade, 1096-1099
IV.1 Overview
IV.2 Nicaea
IV.3 Antioch
IV.4 Jerusalem
IV.5 Reasons for Success
V. The Fourth Crusade, 1202-1204
V.1 Overview
V.2 Zara
V.3 Constantinople I
V.4 Constantinople II
V.5 Reasons for Success
VI. Conclusion
VII. Notes
VIII. Bibliography

I. Introduction

            A siege is a military blockade of a certain place in order to conquer. The term is from the Latin word "sessio" which means "seat." In the simplest term, the attackers try to take over the place before they have to give up due to lack of supplies. Both sides use various methods to defend or attack the place.
            During the Crusades 1096-1204, there were two highly successful campaigns. The first was the initial march to Jerusalem (First Crusade 1097-1099), lead by Bohemund Prince of Taranto (1). The second one was the Crusaders' diverted campaign into the Byzantine Empire during the Fourth Crusade (1202-1204).
            The reason why the two campagains were successful can be found at their success at sieges. Unlike many other forces, these campagins were powerful and effective at sieges, prevailing in most of them, which allowed them to save time and energy. This paper will start by showing the elements which were needed to win a siege. The latter part of the paper will focus on specific sieges, with three examples per campaign.
            In the end, this paper will show that sieges were not just merely cases of soldiers running against the walls. Sieges were complex military actions, and a variety of elements, not just one, were pivotal for a successful siege.

II. The Selection of Cases

            The original topic was Sieges in Medieval Warfare. There were numerous sieges during this long period; this paper focusses on the sieges attempted in the First and the Fourth Crusades, which is about 100 years. There were sieges by Saladin and other Muslim leaders during the time period as well, but this paper will only deal with sieges conducted by the Crusaders. Also, the sieges dealt with are only major sieges, and all of them successful. That is because failed sieges were usually not kept in records. Finally, this paper deals with performing a siege, rather than defending against a siege.

III. Elements of Successful Sieges

III.1 Synopsis
            Bernard Law Montgomery stated in his book "A History of Warfare", that there were three ways of a successful siege. The first was to break the walls. The second was treachery. The third was starving the besieged (2). This is analysis is partially correct. The three ways he mentioned are certainly ways to succeed in a siege. However, this analysis is incomplete in two ways. First, this analysis leaves out morale, one of the most important of a successful siege. Secondly, it views each ways as a separate card. A siege cannot be won out of a single strategy. All five factors must be accomplished to a certain point. Just a single case of treachery cannot break down the walls, nor can an infinite supply of food can make others starve. The five elements mentioned below are based on Montgomery's analysis. To be more precise, starving the besieged has been divided into two parts-complete blockade and reinforcements. Morale has also been added as a fifth element.

III.2 Complete Blockade
            Complete blockade is an easy yet tedious task to accomplish. A complete blockade means covering all entrances to the castle/fortress. Gates, water routes, hidden passways and any other forms of transportation must be blocked for a successful siege. If the blockade is not complete, it can render constant attacks on walls useless because the walls can be fixed easily. Even with siege machines, it is much harder to break a wall than to fix it. With a complete blockade, the fixing becomes impossible. Blockading food also greatly helps. Starvation is a great weapon; a weapon had given keys to many castles.

III.3 Reinforcements
            Reinforcements are always welcome, and they are no exception in sieges. Reinforcements can be additional war materials, water, food, or armed forces. Although reinforcements are sometimes not necessary, many battles have been won by reinforcements. That is because reinforcements strengthen the rest of the four elements. Complete blockade with reinforcement for besiegers means the starvation of the enemy. The attacks on the walls can be maintained longer with reinforcements. Morale rises with addition of reinforcements. The enemy is tempted to betray and give up whenever a large number of reinforcements arrive.

III.4 Constant Attack on the Walls
            This part is always shown at war movies. Soldiers charge at the walls, putting up ladders. Battering rams try to bash down the gates. Trebuchets, mangonels, catapults, ballista and onagers (3) launched projectiles to break the walls. Ladders and siege towers try to overcome the height of the walls. Undermining the walls is an another popular tactic. This constant attack sometimes brought victory, but mostly it was a waste of materials and men. This attack is usually combined with other elements such as treachery and blockade to win. A castle with locked gates and strong defenders is hard to overcome, but a castle with open gates and starved defenders can be overtaken by attacks.

III.5 Morale
            Even with tremendous odds against them, some manage to take over the fortress because of morale. Strong leadership unites the units and keeps them at high morale. Divided attacks or blockades cannot bring the full potential of the army. High morale is essential in any attack.

III.6 Treachery
            Attack from the inside is more painful than one from the outside. This adage applies to sieges as well. Even the strongest fortresses fall because the gates were opened. However, treacheries are very rare and needs special circumstances. The circumstances include constant attacks, which tire the defenders. Reinforcements and blockades exasperate and makes the defender wants to give up. Other elements are needed to succeed making someone betray. Also, treachery does not always apply to large treacheries such as opening the gates of the tower. Some small ones, such as merchants selling food to the attacking army, some solders not fighting to their fullest point because of despair, all of they can be considered small versions of treachery. These small treacheries, though not recorded in most cases, are usually one of the reasons that attackers could take over the castles.

IV. The First Crusade, 1096-1099

IV.1 Overview
            The first crusade was launched in response to the call of Emperor Alexius of Byzantium. The Seljuk Turks were on the rise and had taken over many Byzantine territories, including Jerusalem. Alexius fearing to loose his empire, asked Pope Urban II. for help (4). The first crusade had two main armies. The first army was lead by knights like Godfrey, Tancred, Bohemund, Raymond, and Bishop Puy. This army included most of the leaders and knights, and was the main core of the Crusaders. The second group was the People¡¯s Crusade, lead by Peter the Hermit. This group was rather disorganized and was made up of many men who were poorly equipped. The First Crusade started by reaching Constantinople. From then, the Crusaders took many of the Byzantine lands occupied by the Turks and gave them back to the Byzantines. However, starting from Antioch (1097), the Crusaders set up their own Latin feudatory states instead of returning the lands. This crusade finally ended with the conquest of Jerusalem (1099) (5).

IV.2 Nicaea (May-June 1097)
            The siege of Nicaea was the first major siege of the first crusade (6). Nicaea was a city originally belonging to the Byzantine Empire. However at the time, the Seljuk Turks were in control of the city, and the Crusaders agreed to take the city and return it to the Byzantine Empire. Duke Godfrey, Tancred, and Bohemund first tried to storm the castle with their army. The battle was fierce. The Crusaders tried tactics such as undermining the walls (7).. However, their attempt to undermine the wall failed because the Turks found the tunnels early on in the battle (8).. The Turks' attempt to break through also failed. The Crusaders constantly broke away parts of the walls; however, the defenders kept receiving building materials and reinforcements from across the water - the lake (9). The siege started to turn into a long stalemate. Finally, the Crusaders called for a fleet to be sent by the Byzantine emperor; the emperor complied. The defenders surrendered as soon as they saw themselves besieged in both land by Crusaders and water by Byzantines (10).
            This siege demonstrates that in order to successfully conclude a siege, a blockade is essential. The Turks could have held the Crusaders off indefinitely if they could still get the materials by ship. Since it is much easier to repair the wall than to break it, it is possible to conclude that the Crusader victory could not have been won without the naval support from the Byzantines. However, the Crusader¡¯s roles are not to be undercut, since just a naval blockade alone would have not won the siege. A constant attack force to chip away the walls and a blockade force to stop reinforcements are both needed to attain surrender.

IV.3 Antioch (October 1097-June 1098)
            The siege of Antioch iconsists actually of two sieges, not one. The first siege was by the Crusaders against the city of Antioch defended by the Seljuk Turk Yaghi-Siyan. The second siege was laid by Seljuk Turk Kerbogah against Crusaders. The first siege by the Crusaders was successful and the second by the Turks was not. This paper will not discuss the second siege, because it was not conducted by the Crusaders.
            Antioch has been controlled by Turks since 1085, and it was a well-fortified city (11). Again, the Crusaders agreed to take the city for Alexius, the emperor of Byzantium. Godfrey, Bohemund, and Raymond agreed to siege the city, rather than an all-out assault However, Tower of the Two Sisters of south and at the northwest corner the Gate of St. George was not blocked by the crusaders. This allowed Yaghi-Siyan a constant supply of food and resources (12). By Christmas, the Crusader forces were in desperate need of food, but the Turks showed no signs of surrender (13). They had exhausted all food in that region, and needed to search other regions for food. Bohemund agreed to expedite to the land of Saracens. Yaghi-Siyan took the chance and attacked the remainder of the besieging Crusaders, while Duquq of Damascus attacked Bohemund. Although Crusaders prevailed in both battles, they had less food than ever (14). This lead to mass desertion in the crusaders' army. including leaders like Peter the Hermit and Tatius, the representative of the Byzantine Empire. Although Peter returned, Tatius did not. Bohemund argued that because Tatius had deserted the army, the Byzantine Empire had no longer a claim for Antioch (15). Ridwan of Aleppo took opportunity of this rift between the leaders of Crusaders to attack the Crusaders, but Crusaders defeated him (16). Meanwhile, Bohemund successfully bribed Pirus, one of the captains of Antioch to give up three towers that he held to the Crusaders (17). Pirus did so because his part of defense was completely blocked. Crusaders, in a sense, did a complete blockade though it was around only a part of the castle. Crusaders were united by the rumor that a gigantic force was coming against them, which lead to a strong attack over the towers. With Crusaders flowing into castle through the towers, Yaghi-Siyan had no chance to defend the castle. The crusaders "found" the Holy Lance in the city and defeated an attack by Kerbogha the Turk, which concluded the siege (18).
            This siege marks three important factors of siege; blockade, treachery, and leadership. The Crusaders made another fatal mistake in allowing Yaghi-Siyan to get food. This mistake led to their critical situation on Christmas when their siege almost failed. With defenders supplied with food and attackers not, the attackers have almost no chance of winning. However, they overcame that mistake by successfully inducing the betrayal of Pirus. A complete blockade was another successful point in this, while the complete blockade was limited to a certain part of the castle. Walls are the strongest defense of the castle, but one treachery can overcome this. One interesting point is that when the Turks took Antioch, they used treachery as well. Another point to acknowledge is leadership. Another reason that the Crusaders won was because of there leadership. They were strongly united under faith and their belief in God. They were in their greatest danger was when their leaders were split. Holy Lance and other "discoveries" helped them to unite. Muslims, on the other hand, had weak unity as shown in treachery of Pirus.

IV.4 Jerusalem (June-July 1099)
            With Bohemund not leaving from Antioch and bishop Puy, who was the representative of Rome, dead, the leadership of the Crusaders was in disarray. The remaining leaders, Raymond, Tancred, and Godfrey all differed on what course of action to take (19). But by June 7th ,they had settled their differences and the army of Godfrey reached the city of Jerusalem (20). Iftikhad ad-Daula calmly defeated the first wave of Crusaders. After a few days, Raymond, Tancred, and Godfrey laid a siege that stretched from the Northern Wall to the Zion mounitain (21). Altough they did suceed in a complete blockade, there was one major problem. In Jerusalem, the only way to get water was from the wells of Jerusalem. The unorganized state of the Crusaders squandered the remaining precious water (22). With water running low, the Crusaders were at low morale. Then two incidents turned the tide of the battle. New reinforcements from christian ships at Jaffa helped Crusaders have water (23). Also, priest Peter Desiderius claimed that if they fasted for three days and marched barefoot, the city would fall like Biblical example of Jericho. Strengthend by such morale-boosters, Crusaders took over the city after following the orders of Desiderius. The religious frenzy continued and more than 40,000 denizens of Jersualem were killed (24).
            A complete blockade and morale were the keys to victory in this matter. The multitude of forces allowed a complete blockade, which greatly weakened the defences of Jerusalem. Without food, Iftikhad ad-Daula had a hard time resisting the crusaders. More important factor was the morale. The thought of recovering the holy city and the vision of Jericho by Peter Desiderius were key factors in delivering the city to the Crusaders.

IV.5 Reasons for Success
            Of the five elements, the Crusaders did not always rely on treachery or reinforcements. Their skills of sieges were not yet perfect to pull of a complete blockade in some cases. Most of the hard times of their sieges came from their inability to do a complete blockade. At Antioch, where they did not have a complete blockade, they had a comparatively hard time conquering the city. Still, it shows at least a complete blockade in a part of the castle was necessary for a victory. As shown at Nicaea, once a complete blockade was done, the city surrendered quickly. However, there greatest strength lay in their high morale. They believed that they were protected by God, and their morale was rarely put down. Their numerous numbers did help in constant attacks on walls. Still, the biggest success factor of the first Crusader¡¯s sieges can be attributed to their high morale and unity.

V. The Fourth Crusade

V.1 Overview
            The 4th crusade was planned to conquer Egypt. Venetian ships would transport them for 85,000 marks and half of their conquest (25). However, because of Byzantine politics and shortage of money, Crusaders agreed to capture the Byzantine city of Zara for Venice instead of payment for their passage (26). This led to an excommunication of the Crusaders by the pope in Rome. They went on to attack Constantinople, helped Byzantine throne contenders Isaac II and Alexius IV to defeat their rival, Byzantine Emperor Alexius III. However, they were not paid and left Constantinople. After Alexius V defeated Isaac II and Alexius IV, the Crusaders once again besieged Constantinople and sacked it. This led to an eventual downfall of the once mighty Byzantine Empire.

V.2 Zara (November 1202)
            This was the first major action of the Fourth Crusade, as well as the first attack on Catholics by the Catholic Crusaders (27). This was a siege that could have been avoided. The people of Zara first offered a peaceful surrender (28). The Doge of Venice declined, saying that he needed to talk with the barons. But by the time the barons agreed, the people of Zara had changed their minds (29). There were protest from the Pope and the people of Zara about attacking fellow Christians, but Crusaders ignored the protests and attacked (30). The 60 warships and 300 mangonels were more than a match for a city like Zara. The warships broke the sea defenses, and the mangonels tore down the walls. The city surrendered in 5 days. However, this victory also resulted in the excommunication of the Crusaders.
            This shows a classic demonstration of the five elements working together. The warships blocked the waterway while the armies blocked the roads. Venetian ships supplied reinforcements plentifully. Mangonels constantly tore down the walls. The morale was considerably high, since it was the first battle. Minor treacheries were done by those who wanted to surrender in the first place.

V.3 Constantinople I (July 1203)
            Promising 200,000 marks and a unification of church (the Greek Church with Rome), Alexius (to be Alexius IV) persuaded the Crusaders to attack Constantinople (31). He claimed to be the rightful heir to the throne of the Empire, which was a morale booster for the Crusaders. The corrupt Byzantium navy could not stop the Crusader's fleet (32). They landed in front of the tower of Galata, which was on the tip of the Golden Horn. This place was important because between Galata and Constantinople there was long, thick chains which prevented ships from crossing. The Greeks attacked from Galata first, but the Crusaders beat them and took Galata (33). After that, the Crusaders could attack from either the sea or the land. It was agreed that Venetians would attack from the sea and the barons from the land. The land attack was fought off by Varangian Guards, but the naval attack captured 25 towers (34). A general charge by the Byzantines forced a retreat of all Crusaders. However, during the night, Alexius III of Constantinople fled, leaving Crusaders victorious and Alexius IV and Isaac II as co-emperors.
            A combination of attacking the walls and treachery won the great fortress of Constantinople. The attacks by Venetians were successful; however the Byzantines had enough army to drive them off. It was the treachery if the emperor that played a large part in this battle. However, it is obvious that the onslaught of the Venetians had a deep psychological impact on the emperor.

V.4 Constantinople II (April 1204)
            After Alexius IV and Isaac II took over, the nobles grew dissatisfied with them, especially about the payments that they had to make to the Crusaders. Murtzuphlus was one of the dissatisfied nobles (35). He tricked Alexius IV into attacking the Venetian ships which led to Alexius IV¡¯s downfall. Isaac II died, leaving Murtzuphlus as the leader. Murtzuphlus became Alexius V and heightened the sea walls, prepared against an assault (36). The first charge by the Crusaders was beaten off by "Greek Fire", a fire that had been designed not to be put out. The second assault was successful largely because of the fireproof coverings had been placed on the Venetian ships (37). Crusaders quickly took over the sea walls tower by tower. Soon, the whole of crusader army was inside Constantinople. The Imperial cavalry led by disgruntled nobles were beaten soundly. Alexius V and his Varangian Guards lost a street by street combat, and when they surrendered, the sack of Constantinople began. Eager to get the 200,000 marks promised, the Crusaders looted the city. Countless treasures and relics were stolen, and 400,000 marks was the "official" loot of the Crusaders (38).
            The reinforcements were one of the decisive factors of this siege. The Crusaders were replenished across the Golden Horn, while the Byzantine Empire could not get anymore soldiers or materials. The city of Constantinople had not allowed a navy for such a long time that they were not accustomed to not being reinforced. Also, Crusaders were smart, avoiding the land walls and attacking the sea wall instead. The low morale of the Imperial Calvary was the final straw that broke the Byzantine Empire.

V.5 Reasons for Success
            The morale was comparatively low - they were fighting against fellow Catholics, not against infidels for the holy city. However, the control of the sea was the key. The Venetian navy allowed a complete blockade much easier, and the reinforcements came much quicker through the sea. It also proved to be an effective wall attacking tool during the sieges of Constantinople. Better machinery and armor was another reason that the Crusaders were victorious. Also, although the morale was lower compared to the First Crusade, the morale was still high considering the chaotic situation of the Byzantines. This Crusade classically shows the harmony of the five factors.

VI. Conclusion

            In movies, sieges look like a simple but costly job. Have enough men, and some of them are bound to cross the wall. However, it is not so in real battle. Sieges were a terribly complicated war that took a long time to win and even longer to lose. A constant blockade must stop supply to go into the fortress. Reinforcements should keep good supply of food, water, men and materials. Constant attacks to the wall with siege machines should demoralize and tire the defenders. Morale needs to be kept high for the final charge. Treachery should open the strongest gates and the strongest defenses. Even when these five factors fell into action, there are numerous sieges which failed. Even missing one of these crucial elements could be critical in siege. Antioch is the good example. Before a complete blockade of the castle, the Crusaders had no chance to take over. However, the complete blockades of the towers of Pirus lead to a treachery of Pirus, which won the siege. As the examples above showed, the harmony of the five elements was needed. The intention of this paper was to show the complexity of sieges through the two crusades. The First Crusade demonstrated how high morale can win the siege. The citiess in the Fourth Crusade were taken because of their better blockade skills. There were different reasons why the Crusaders were successful, but it was a common factor that all five elements were fulfilled. A siege is not a mere battle. It is an artwork where every stroke must be made in order to be complete.

VII. Notes

(1)      1st Crusade, from Military History Encyclopedia on the Web
(2)      Montgomery 2004
(3)      Wikipedia : Siege
(4)      1st Crusade, from Military History Encyclopedia on the Web
(5)      Wikipedia : First Crusade - March to Jerusalem
(6)      Nicaea, from Military History Encyclopedia on the Web
(7)      Krey 1921 pp.101-103
(8)      Nicaea, from Military History Encyclopedia on the Web
(9)      Krey 1921 pp.103-105
(10)      ibid.
(11)      Wikipedia : Siege of Antioch
(12)      ibid.
(13)      Krey 1921 pp.132-134
(14)      ibid.
(15)      ibid.
(16)      Wikipedia : Siege of Antioch
(17)      Krey 1921 pp.132-134
(18)      Krey 1921 pp.153-155
(19)      Wikipedia : Siege of Jerusalem
(20)      ibid.
(21)      Krey 1921 pp.242-243
(22)      ibid.
(23)      ibid. pp.242-248
(24)      Wikipedia : Siege of Jerusalem
(25)      4th Crusade, from Military History Encyclopedia on the Web
(26)      4th Crusade, by Steven Lowe
(27)      Wikipedia : Siege of Zara
(28)      Joinville and Villehardouin pp.46-49
(29)      ibid.
(30)      Wikipedia : Siege of Zara
(31)      4th Crusade, from Military History Encyclopedia on the Web
(32)      4th Crusade, by Steven Lowe
(33)      Joinville and Villehardouin pp.66-73
(34)      4th Crusade, by Steven Lowe
(35)      Joinville and Villehardouin pp.75-80
(36)      Joinville and Villehardouin pp.87-93
(37)      4th Crusade, by Steven Lowe
(38)      4th Crusade, by Steven Lowe

IX. Bibliography

Note : websites quoted below were visited in September 2007.
1.      Marshal Viscount Bernard Law Montgomery, A History of Warfare, Korean edition Seoul 2004
2.      August C. Krey, The First Crusade: The Accounts if Eyewitnesses and Participants, Princeton UP 1921, contains accounts of the First Crusade by of Gesta and Raymond d'Aguiliers
3.      Joinville and Villehardouin: Chronicle of Crusades, London : Penguin Classics, 1963, accounts of the Fourth Crusade
4.      Article : Sieges, in : David Eggenberger, Encyclopedia of Battles, NY : Dover Publications 1985
5.      Article : Siege, from Wikipedia,
6.      Article : First Crusade, from Wikipedia,
7.      Article : Siege of Antioch, from Wikipedia,
8.      Article : Siege of Jerusalem, from Wikipedia,
9.      Article : Siege of Zara, from Wikipedia,
10.     Chapter : 1st Crusade, from Military History Encyclopedia on the Web,
11.     Chapter : Battle of Nicaea, from Military History Encyclopedia on the Web,
12.     Chapter : Battle of Antioch, from Military History Encyclopedia on the Web,
13.     Chapter : Battle of Jerusalem, from Military History Encyclopedia on the Web,
14.     Chapter : 4th Crusade, from Military History Encyclopedia on the Web,
15.     Steven Lowe, The 4th Crusade and the Fall of Constantinople,
16.     The Sack of Constantinople 1204, from Agia

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