now destroyed army to join the Fifth Crusade. Instead, King George's sister Rusudan had to write to the Pope Honorius III to explain that they could not assist the Crusade because their whole army had been disintegrated. Though Georgia lay defenseless after these catastrophic defeats, the Mongol mission was to raid and scout, not conquer. After ravaging Georgia, the Mongols cut across the Caucasus Mountains during the winter to get around the Derbent Pass. The Mongols were tricked by their guides into taking a perilous route and emerged from the mountains exhausted, only to be confronted with a far larger steppe coalition army. Using clever diplomacy, Subutai isolated and defeated the Alans, Circassians, and Don Kipchaks/Cumans in detail. After plundering the southern Russian steppes, the Russian princes united with the retreating Cuman confederacy to defeat the Mongols with an 80,000 man host. Despite being heavily outnumbered, Subutai sacrificed the 1,000 men of his rear guard to induce the coalition army to recklessly pursue him and become separated. The plan worked, but strategic advantage came at a high price. In all likelihood the 1,000 men were led by Jebe who was killed by some Kipchaks. As expected the coalition army pursued the Mongols and after retreating for 9 days, Subutai suddenly turned and crushed the combined Rus' and Cuman army at the Kalka (31 May 1223). Arab historian Ibn al-Athir mentions a campaign against Volga Bulgaria, where the Mongol army was defeated in late 1223 or early 1224 (620). According to Ibn al-Athir, 4, 000 men survived from the Mongol side in this battle. The remaining army proceeded to Desht-i Qipchaq, where they joined the army of Jochi, but historians have doubted this account in light of the Mongols seeking out and defeating the Qangli Turks in southern Russia shortly afterward. Invasions of the Xi Xia and Jin China (1207, 1209, 1211–1215, 1226–27) In the initial invasion of the Jin in 1211, Subutai served with Jebe's army that attacked the Chinese forts around the eastern edge of the Great Wall (not the Ming Great Wall). In late 1211 he was the first to scale the walls of the key fortress of Huan-Chou, and took part in the ambush of a major Jin army at Wu Sha Pao and the climactic battle of Yehuling. In 1212, he may have served with Jebe during the latter's daring capture of Liaoyang, and in 1213