By the end of June, word came that a Fatimid army was marching north from Egypt. The mounting pressure forced the Crusaders to act quickly. Final assault On 17 June 1099, 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. Robert of Normandy and Robert of Flanders procured timber from the nearby forests. Under the command of Guglielmo Embriaco and Gaston of Béarn, the Crusaders began the construction of their siege weapons. They constructed the finest siege equipment of the 11th century 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; now they were ready to attack The Fatimids kept an eye on the preparation by the Franks and they set up their mangonels on the wall in the firing range once an assault began. On 14 July 1099, the Crusaders launched their attack. Godfrey and his allies were positioned towards the Northern wall of Jerusalem, and their priority was to break through the outer curtain of the walls of the city. By the end of the day they penetrated the first line of defense. On the South Raymond of Toulouse's forces were met with ferocious resistance by the Fatimids. On 15 July the assault recommenced in the Northern front; Godfrey and his allies gained success and the Crusader Ludolf of Tournai was the first to mount the wall. The Franks quickly gained a foothold on the wall, and as the city's defenses collapsed, waves of panic shook the Fatimids. Aftermath Crusaders enter Jerusalem On 15 July 1099, the crusaders made their way into the city through the tower of David and began massacring large numbers of the inhabitants; Muslims and Jews alike. The Fatimid governor of the city, Iftikhar Ad-Daulah, managed to escape. According to eyewitness accounts the streets of Jerusalem were filled with blood. How many people were killed is a matter of debate, with the figure of 70,000 given by the Muslim historian Ibn al-Athir (writing c.1200) considered to be a considerable exaggeration; 40,000 is plausible, given the city's population had been swollen by refugees fleeing the advance of the crusading army. Massacre The aftermath of the siege led to