March 16 – Siege of Montségur: French forces capture and destroy Château de Montségur in Languedoc, after a 9-month siege. Some 200 'heretics' (perfecti and credentes) are burnt in a bonfire, near the foot of the castle. This marks the final defeat of the Cathars (or Albigensians); the followers become scattered fugitives, meeting in forests and mountain wilds.[1]
December – King Louis IX (the Saint) falls desperately ill of a severe malarian infection. Near-death, he vows that if he recovers he will set out for a crusade. Louis' life is spared and as soon as his health permits him, he takes the cross and immediately begins preparations for the Seventh Crusade.[3]
Levant
June – Khwarazmian forces (some 10,000 men) invade Syrian territory, ravaging the land and burning the villages. As Damascus is too strong for a siege, they attack Galilee, past the town of Tiberias – which they capture. The Khwarazmians attack further southward through Nablus towards Jerusalem.[4]
July 15 – Siege of Jerusalem: Khwarazmian horsemen attack and sack the 'holy city' of Jerusalem. There is bloody fighting in the streets, the Khwarazmian force their way into the Armenian Quarter, where they decimate the Christian population, and drive out the Jews. The city is left in a state of ruin.[5]
August 23 – The Tower of David surrenders to the Khwarazmian forces, some 6,000 Christian men, women and children march out of Jerusalem. As they move along the road toward Jaffa, they see crusader flags waving on the Walls of Jerusalem. Returning, some 2,000 of them are massacred.[6]
October 4 – The Crusaders assemble a force of some 1,000 cavalry and 6,000 men outside Acre, after hearing that Jerusalem is sacked by the Khwarazmians. They are joined by the Ayyubid forces (some 4,000 men) of Damascus and Homs – while Emir An-Nasir Dawud brings his army from Kerak.[7]
June 7 – Pope Innocent IV is driven from Rome by imperial forces of Emperor Frederick II, and travels secretly in disguise to Sutri. Genoese galleys prepared by his relatives are waiting for him at the port of Civitavecchia to take him to Genoa.
October 5 – Innocent IV flees to France and travels to Lyon, where he arrives on November 29. Although the city is nominally subject to the Holy Roman Empire, Innocent falls under the protection of Louis IX.
December 27 – Innocent IV summons a general council to meet in Lyon (some 140 bishops eventually come) to attend what becomes later the First Council of Lyon.
