The siege of Jerusalem from 7 June 1099 to 15 July 1099 marked the successful end of the First Crusade, and the founding of the Kingdom of Jerusalem soon afterwards. The siege was carried out by the Christian forces of Western Europe mobilized by Pope Urban II after the Council of Clermont in 1095. The city had been out of Christian control since the Muslim conquest of the Levant in 637 and had been held for a century first by the Seljuk Turks and later by the Egyptian Fatimids. After an initial unsuccessful attack on 13 June, the crusaders constructed several siege engines including a siege tower and a battering ram enable them to enter the city on 15 July 1099. Following the siege thousands of Muslims and Jews were massacred by the Crusaders.
Background
In 1095, Pope Urban II called for a crusade at the Council of Clermont (Deos lo vult). In addition to aiding Byzantium, which was under threat from the Seljuks, the goal was to reach the Holy Land and liberate Jerusalem. Following their departure from Constantinople in April 1097 and their crossing of the Taurus Mountains, the main forces of the First Crusade reached northern Syria in the fall of 1097. While Baldwin of Boulogne marched eastward and, in the spring of 1098, founded the first Crusader state, the County of Edessa, the main army laid siege at Antioch in October 1097. After the city fell in June 1098 and the subsequent victory over a Seljuk relief army led by Kerbogha, the advance came to a standstill.
Months of political power struggles among the leaders between Bohemond of Taranto and Raymond IV of Toulouse, as well as epidemics and supply shortages, delayed the advance. Upon taking command Raymond of Toulouse resumed the march southward in January 1099. Following the Levantine coastline, the troops avoided protracted sieges of heavily fortified cities. Instead, they concluded agreements with local Muslim rulers, or paid tribute. At the end of May 1099, the army left the coastal region at Jaffa and reached the vicinity of Jerusalem on 7 June, 1099.
Prelude
Since the 10th century Jerusalem had been under Fatimid rule. The defences of the city dated back to the time of Emperor Hadrian and had been maintained and reinforced since then.The stone walls around the city stretching four kilometers long, were three meters thick and 15 meters high. There were five major gates each guarded by a pair of towers.The city was protected on three sides by steep valleys and gorges: to the east by the Kidron Valley, to the southeast by the Hinnom Valley, and to the west by the Tyropeon Valley. Only the southwest, over Mount Zion and along the entire length of the northern wall, offered terrain favorable for an attack.
Upon learning that a Christian army was marching to Jerusalem Iftikhar ad-Dawla the Wālī (Governor) of the city began making preparations to defend the city. He made sure that no resources, whether water, food or wood were available for his enemies in the vicinity of the city. He also expelled Syrian Christians who might be sympathetic to the crusading army, whereas all Jewish were permitted to stay.Anticipating that the crusaders would built siege engines, he ordered all available timber and rope to be used for build more mangonels for the city. In the event that the Crusader machines proved capable of damaging the stone walls Iftikhar ordered to sew bags filled with straw to be placed at strategic points beside the walls. These bags could be lowered on ropes to buffer the impact of flying rocks.
From the estimated 20,000 to 75,000 troops that have assembled at Nicaea between 12,000 and 14,000 had reached Jerusalem on 7 June. The cavalry consisted of 1,200–1,300 men.The garrison defending Jerusalem comprised roughly some thousand Arab and Sudanese troops as well as some 400 egyptian elite cavalry.
With most wells and cisterns rendered unusable, the crusaders faced a lack of water supply. The conditions were further exacerbated by heat, lack of shade and the khamsin. There was only source of water, was the En-Gihon, spring that flowed from the southeast spur of the city. It lay below the ridge that held the very first human settlements in the area, known in ancient times as Zion. Although Gihon could deliever over a million litres a day during the winter month in summer the overall flow dropped considerably. In opposite, the people of Jerusalem obtained all the water from deep cisterns. In addition, there were hundreds of smaller cisterns located under houses and courtyards across the city, which were fed by a system of pipes and channels from flat roofs and paved streets.
Since the Crusaders had insufficient forces to besiege the entire city, they concentrated their strength on the sectors where they could approach the walls. Robert of Normandy posted his troops along the northern wall, opposite the Gate of Flowers (also known as Herod's Gate). Robert of Flanders was stationed on his right, facing the Gate of the Column (also known as St Stephen's Gate or the Damascus Gate). Godfrey of Lorraine covered the north-west corner of the city, extending down to the Jaffa Gate. Tancred joined him here, riding up when the army was already in position and bringing flocks he had acquired on his way from Bethlehem. Raymond of Toulouse stood to the south. Finding that the valley kept him too far from the walls, he moved up to Mount Zion after two or three days. The eastern and south-eastern sectors were left unguarded.
Siege
According to Raymond of Aguilers the first attack was initiated by a prophecy of an old hermit claiming that if the crusaders would attack on 13 June until the ninth hour, it would fall to them.
During the night, the army prepared to attack the city using whatever materials they could find.Despite initial success the attack proved to be a failure, demonstrating the need for more siege engines.
Two days after the failed attack on Jerusalem on June 13, 1099, the leaders of the crusade met to discuss their strategy. Recognizing that divine intervention would not yield the city, they were confronted by the harsh realities acknowledging that the situation, favoured the defenders of Jerusalem. The issue of water supply worsend, leading to deaths from thirst and ambushes while seeking fresh water. The difficulties in obtaining enough water for both the crusaders and their horses threatened their strength and morale, making it unlikely the siege could last months, especially in the Palestinian summer heat. Additionally, rumors indicated that the vizier of Cairo, al-Afdal, was gathering an army to relieve Jerusalem, giving the crusaders only a fortnight to capture the city.
With the option of a long siege to starve the garrison ruled out there were two options left: breaking the walls or climbing over them. While the city's defenses were robust, they were not as formidable as those of Nicea or Antioch. The primary barrier was the inner wall, which stood 12 to 15 meters tall but was not very thick. Built by Fatimid governors after a 1033 earthquake, the wall was drawn closer to the city, using materials from ruined buildings, which excluded some key areas like Mount Zion and the Pool of Siloam but allowed for a stronger, more defensible structure with a shorter perimeter.
After the Seljuk conquest of Jerusalem in 1073, governors such as Atsiz ibn Uwaq, Turtush, and Artug, along with his sons Ilghazi and Suqman, had construced a deep ditch around much of the city to prevent scaling or the use of siege towers. To fortify David's Tower, a dry moat (19 meters wide and 7 meters deep) was dug, isolating it from the city and requiring bridge access. This ditch extended north along the west wall to the Goliath Citadel and further north, becoming a stronghold measuring up to 7 meters deep and 19 meters wide towards the Kidron Valley. A similar ditch reinforced the southern wall.
Moreover, the Seljuks had constructed an extra line of defenses just inside the ditch, consisting of outlying strongpoints, and a subsequent outer wall. This outer wall did not present a significant challenge to attackers, on 13 June the crusaders had dismantled a section with pick axes before advancing to the taller inner wall. Its purpose was to obstruct the line of flight of stones cast on low trajectories from mangonels, preventing the missiles from striking low down on the inner wall. The outer wall was not an independent structure; it was linked to the city at multiple points, which created confined ‘no-man’s land’ zones between the two walls, further complicating the assault for any attackers.
Construction of siege engines
On 17 June the Crusaders heard about the arrival of English and Genoese ships at the port of Jaffa. The English and Genoese sailors had brought all the necessary material with them for the construction of the siege equipment. Searches for timber were also successful. Suitable wood was found over 50 km away, near Nablus. According to Albert of Aachen, a local Christian showed the Franks where to find timber. Ralph of Caen states that Tancred, who was suffering from dysentery, came upon a cave containing around 400 beams of wood while seeking privacy during one of the searches for timber. The beams had been conveniently left there by the Fatimids, perhaps from their siege of the Seljuks. Under the command of Guglielmo Embriaco and Gaston of Béarn, the Crusaders began the construction of siege engines. They constructed the siege equipment in almost three weeks. This included two massive wheel-mounted siege towers, a battering ram with an iron-clad head, and numerous scaling ladders and a series of portable wattle screens.
Situation within the city
The remaining Christians in Jerusalem faced hostility and mistrust from the local population and harsh commands from Iftikhar. Struggling households were forced to share scarce food and endure heavy taxes, with several key figures captured to enforce compliance. The Christian community was compelled to perform labor, including carrying heavy loads at all hours, facing physical coercion from Muslim soldiers. Skilled tradespeople were obligated to work on city defenses, and their homes were often dismantled for materials. Furthermore, they were at risk of being falsely accused of espionage for the crusaders. In reality, some Christians did indeed try to help their fellow believers outside the walls. Tancred, in particular, was collaborating with Syrian Christians outside the walls to establish contacts within the city.
Situation outside the city
The question of who would become ruler of Jerusalem once it had been conquered was constantly present. The leading contender for the honour was Count Raymond of Toulouse. If the Provençal contingent preserved its unity, they could likely assert Raymond's control over the captured city, given that they formed the single largest regional faction within the crusading force. But there were signs of severe tension among the Provençal contingent, particularly between the more loyal followers of the Count and the less dedicated knights. The former followers of Bishop Adhémar, although stationed in the southern camp, were more interested in the regular payments from Count Raymond’s huge war chest. Furthermore, the large number of impoverished non-combatant crusaders who camped with Count Raymond at Mount Zion acted with impunity. Overall, it was far from guaranteed that Raymond could rally everyone to ensure his future rule over Jerusalem.
By contrast, the tone in the northern camp was much more harmonious, despite the diverse composition of the crusading army, comprising many different languages and regions. As Robert of Normandy and Robert of Flanders were eager to fulfil their vows and return home, there was only one obvious choice for the lordship of Jerusalem: Godfrey of Lotharingia. While Tancred aspired to rule towns, cities, principalities and kingdoms, he only had about 40 knights willing to follow him. Thus he accepted the necessity of supporting Godfrey.The physical hardships, coupled with disappointment at the failure of the initial attack and renewed disputes between the princes, caused many crusaders to abandon the crusade. According to Raymond of Aguilers a band of crusaders went down to the river Jordan for rebaptism. After gathering palm branches they moved to Jaffa, hoping to find ships to bring them back to Europe.