A German royal house, members of which held the throne of the Holy Roman Empire (1138–1254), the rivals of the Hohenzollerns. The emperor Henry IV (1084–1106) gave them the duchy of Swabia and in 1138 Duke Conrad became emperor as Conrad III. The family provided many emperors, including Frederick I (Barbarossa) who attempted to build up German power in Italy. The relationship between the papacy and the Hohenstaufen was frequently acrimonious, resulting from their respective claims to land and personal powers. The empire grew to include Germany, northern Italy, and Sicily but proved too large to be managed in the face of papal and Lombard opposition, and the dynasty’s last ruling member, Manfred of Sicily, was killed in battle in 1266.