12 – Sultan as-Salih Ayyub sends an Ayyubid army to Gaza to protect the Egyptian border. At nightfall, Henry of Bar, jealous of the successful ambush of Peter of Brittany, decides to march out towards Gaza with a Crusader force (some 500 knights and 1,000 soldiers). Although warned by Theobald I, Henry orders to set up camp in a flat terrain surrounded by sand dunes near Gaza. November 13 – Battle of Gaza: The Crusader army led by Henry of Bar is defeated by the Egyptians near Gaza. More than a thousand men are slaughtered, including Henry himself. Six hundred more are captured and carried off to Egypt. Among them are Amaury VI de Montfort and Philippe de Nanteuil – who, in the dungeons of Cairo, writes a Crusade song about the failure of the expedition. December 7 – Ayyubid forces under An-Nasir Dawud march on Jerusalem, which is largely undefended. The garrison of the city surrenders to Dawud, after accepting his offer for a safe-conduct to Acre. Dawud destroys Jerusalem's fortifications, including the Tower of David. Meanwhile, Theobald I (losing many men underway) moves with the remnants of the Crusader army northward to Acre. Mongol Empire The Mongol invasion of Kievan Rus': The Mongols under Batu Khan continue their campaign across the Pontic Steppe. After devastating the Crimea and campaigning against the Circassians in the Caucasus, they turn towards the Kievan Rus'. In March, Pereyaslavl, capital of the Principality of Pereyaslavl, is sacked by the Mongols. October 18 – Sack of Chernigov: The Mongols led by Batu Khan attack Chernigov, the garrison rallied outside the walls to face the Mongols in a pitched battle. Prince Mstislav III Glebovich comes to help with his troops, they are slaughtered by Mongol catapults. The city is pillaged as are the towns in the surrounding countryside. By topic Arts and Humanities In England the central tower of Lincoln Cathedral collapses. Religion March 20 – Gregory IX renews the excommunication of Frederick II, while he is at his court in Padua. Frederick responds by expelling the Franciscans and Dominicans from Lombardy. Births June 17 or June 18 – Edward I (Longshanks), king of England (d. 1307) December 17 – Kujō Yoritsugu, Japanese ruler (shogun) (d. 1256) Álvaro (the Castilian), Spanish nobleman and knight (d. 1268) Balian of Arsuf, Cypriot nobleman (House of Ibelin) (d. 1277) Constance of Aragon, Spanish princess (infanta) (d. 1269) John