Foreign policy Yuri II conducted an active foreign policy, largely seeking to expand Vladimir's influence while avoiding major military conflicts. Between 1220 and 1234, his forces, often in alliance with Novgorod, Ryazan, and even Lithuanian troops, undertook 14 campaigns. The only three of these to result in battle were victorious. The foundation of Nizhny Novgorod led to conflicts with the neighbouring
Mordvins. Vladimir's forces launched campaigns against them in 1226, 1228, 1229, and 1232, suppressing opposition to Vladimir's expansion. Yuri also intervened in the affairs of other Rus' principalities and the Baltics. When the
Mongols first approached in 1223, he sent a detachment under his nephew Vasilko to aid the southern princes, but it arrived in
Chernigov too late to participate in the disastrous
Battle of the Kalka River. A subsequent conflict with Novgorod in 1224, however, cost the Rus' their last stronghold in the Baltics,
Yuryev (Tartu), which was captured by the Germans.
Mongol invasion and death In the winter of 1237, the Mongol army led by
Batu Khan invaded the
Principality of Ryazan. The princes of Ryazan appealed to Yuri for aid, but he was hesitant to commit his forces. According to some chronicles, he treated the Mongol envoys who arrived in Vladimir with disdain. He sent his son Vsevolod with a force to assist Ryazan, but it was too late. After Ryazan was destroyed on 16 December, Batu's army advanced towards
Kolomna. Yuri's army, led by his son Vsevolod and the voivode Yeremey Glebovich, was soundly defeated at the
Battle of Kolomna. Vsevolod fled to Vladimir, while Glebovich was killed. Yuri himself was killed on 4 March 1238, in the
Battle of the Sit River, when the Mongol commander
Burundai surprised and defeated the army of Vladimir-Suzdal. Bishop Kirill of Rostov later found Yuri's decapitated body on the battlefield and brought it to Rostov for burial. His head was later found and reunited with his body. In 1239, his brother and successor,
Yaroslav II, solemnly transferred his remains to the Dormition Cathedral in Vladimir. == Legacy and assessment ==