Timber and Fire - How Jerusalem was captured by Crusaders

Ercole de Roberti Destruction of Jerusalem
Source: wikimedia commons

Mid-June 1099 - Genoese fleet anchored at Jaffa, at this time just small natural harbour, closest to Jerusalem. They had come primary to explore new avenues for commerce. For Baldwin, crusaders leader in this time, they provide needed naval power. He offered them generous term - they can create independent trading enclave in any settlement or city taken by Crusaders with sailors help. In addition experienced and  skilled Genoese craftsman strengthen engineering skills of Crusaders which combined with local Christian knowledge about timber sources allow Crusaders to start building siege machinery. Muslim used normal tactic to fight this timber siege towers - fire but sometimes with unexpected role change:

"With one last mighty charge the Franks sent it crashing into the outer wall, creating a massive fissure; indeed, the ram’s momentum propelled it so far forward that the Fatimid troops atop the ramparts feared that it might even threaten the main walls, and thus rained ‘fire kindled from sulphur, pitch and wax’ down upon the dreadful weapon, setting it alight. At first the crusaders rushed in to extinguish the flames, but Godfrey soon recognized that the charred remains of the ram would block the advance of his great siege tower. So, in an almost comically bizarre reversal of tactics, the Latins returned to burn their own weapon, while the Muslims vainly sought to preserve its obstructive mass, pouring water from the ramparts. Eventually, the Christians prevailed and by the end of the day the northern Franks had succeeded in penetrating the first line of defence, opening the way for a frontal assault on the main walls."  Source: Asbridge, T. "The Crusades: The Authoritative History of the War for the Holy Land", Kindle edition, p.98

When situation became more serious, Iftikhar al-Dawla, Fatimid governor of Jerusalem, decide to use a kind of Greek Fire:

"They had prepared a huge wooden spar, soaked in a combustible material, akin to Greek fire (a naphtha-based incendiary compound), which could not be extinguished by water. This beam was set alight and then hefted over the walls to land in front of Godfrey’s engine as a flaming barrier." Source: Asbridge, T. "The Crusades: The Authoritative History of the War for the Holy Land", Kindle edition, p.99

Hand-siphon, a portable Greek Fire thrower. 
Detail from the medieval manuscript
Codex Vaticanus Graecus 1605.
Source: wikimedia commons

However Franks, once again supported by local Christian knowledge, already know how to quell the flames of Greek Fire.

"Luckily for the Latins, they had been tipped off by local Christians about the one weakness of this terrible, impervious fire: it could be quenched by vinegar. Godfrey had thus stocked the tower with a supply of vinegar-filled wineskins, and these were now used to douse the flaming conflagration." Source: Asbridge, T. "The Crusades: The Authoritative History of the War for the Holy Land", Kindle edition, p.99

Finally it was also fire that decide about overwhelming city by Crusaders. Just in the middle of assault Gotfryd z Bouillon realized that nearby city tower and part of wall are burning (most probably because of careless use of Greek Fire). 

"In one moment there were a brief fire on the walls. Godfrey saw it and make the bridge out of his siege tower. The walls were bridged and Muslim defenders runs for theirs lives. The Christians at last could capture the holy city of Jerusalem" Source: THE CRUSADES: CRESCENT & THE CROSS, History Channel

That's how Crusaders with help of timber siege tower and unexpectedly fire conquer theirs ultimate goal - Holy City of Jerusalem. 

Related posts: 

• Antioch 1098 AD - Bohemond and Firuz
• West come to East

Primary sources:

[1] Asbridge, T. "The Crusades: The Authoritative History of the War for the Holy Land", Kindle edition
[2] Phillips, J. "Holy Warriors: A Modern History of the Crusades", Kindle edition

Secondary sources:
[3] About.com Military History - First Crusade: Siege of Antioch
[4] Internet History Sourcebooks Project

Videos:
[5] THE CRUSADES: CRESCENT & THE CROSS, History Channel