After the death of Batu Khan (the founder of the Golden Horde) in 1255, his dynasty flourished for a full century, until 1359, though the intrigues of Nogai instigated a partial civil war in the late 1290s. The Horde's military power peaked during the reign of Uzbeg Khan (1312–1341), who adopted Islam. The territory of the Golden Horde at its peak extended from Siberia and Central Asia to parts of Eastern Europe from the Urals to the Danube in the west, and from the Black Sea to the Caspian Sea in the south, while bordering the Caucasus Mountains and the territories of the Mongol dynasty known as the Ilkhanate.