There is evidence that the Saxons, as well as Slavic tributaries such as the Abodrites and the Wends, often provided troops to their Carolingian overlords. The dukes of Saxony became kings (Henry I, the Fowler, 919) and later the first emperors (Henry's son, Otto I, the Great) of Germany during the 10th century, but they lost this position in 1024. The duchy was divided in 1180 when Duke Henry the Lion refused to follow his cousin, Emperor Frederick Barbarossa, into war in Lombardy.