By 1259, following the fragmentation of the Mongol Empire after the death of Möngke Khan, the Golden Horde became a fully autonomous political entity. It absorbed and replaced earlier nomadic confederations, notably the Cuman-Kipchak federation, and established itself as a dominant force in Eurasia. Batu Khan led the infamous Mongol invasions of Kievan Rus’, Poland, and Hungary between 1237 and 1242. The destruction wrought during these campaigns allowed the Horde to subjugate key principalities of Rus’, which became tributary states. Batu’s forces halted their European campaigns only after the death of Ögedei Khan in 1241, which required Mongol leaders to...