100,000 Mongol, Turks and Persian forces into Europe). In December, Batu Khan sends envoys to the Rus' court of Grand Prince Yuri Igorevich and demands the submission of the capital Ryazan (or Old Ryazan). Battle of Voronezh River: Grand Prince Yuri II of Vladimir supported with border princes of Ryazan, Murom, and Pronsk gather their forces and make a stand on the Voronezh River, waiting for reinforcements from Vladimir. The Mongols under Batu Khan overrun the Rus' forces, who are scattered. Yuri retreats to Ryazan, while some troops withdraw to Kolomna and join the army of Vladimir-Suzdal. December 16–21 – Siege of Ryazan: The Mongols under Batu Khan lay siege to Ryazan. The townspeople repel the first Mongol attacks but after 5 days the city walls are breached by Chinese catapults. On December 21, the Mongols storm the walls and plunder the capital, killing Yuri Igorevich and all inhabitants. Yuri II of Vladimir stood by and does nothing to intervene while Ryazan burns. December – Siege of Kolomna: Rus' forces under Yuri II of Vladimir are besieged and annihilated at Kolomna by the Mongols. Yuri barely escapes to Yaroslavl. The capital of Vladimir is left defenseless – as it is taken after just 2 days. Yuri's wife Agatha (sister of Michael of Chernigov) and all his family die in Vladimir when a church where they have sought refuge from the fire collapses. Levant Spring – Al-Ashraf Musa, Ayyubid ruler of Damascus, assembles his allies and secures his active support of Kayqubad I, Sejuk ruler of the Sultanate of Rum. A civil war seems inevitable when Kayqubad is poisoned during a feast at Kayseri, on May 31. Meanwhile, the Seljuks strengthen the fortresses in the eastern provinces against the Mongols. August 27 – Al-Ashraf becomes dangerously ill and dies after an 8-year reign. He is succeeded by his brother As-Salih Ismail – who defends Damascus against his elder brother Al-Kamil, Ayyubid ruler of Egypt. In October, Ismail has the suburbs burnt to prevent the Egyptian forces from shelter. By topic Cities and Towns Cölln, twin city of the later built Alt-Berlin (or Old Berlin), is founded on the Fischerinsel. The town becomes a trade center, which is linked with Magdeburg and Frankfurt an der Oder. Elbląg is founded by the Teutonic Order under Grand Master Hermann von Balk. He constructs a fortified stronghold on the banks of the Elbląg River (modern