As Luitpold remained a loyal supporter of the Carolingian monarch Arnulf of Carinthia and his son Louis the Child, he enjoyed their support and was entrusted with the defence at the Hungarian and Moravian borders. In 898 he fought successfully against Mojmír II, the king of Great Moravia, on behalf of the king's rebellious brother Svatopluk II and forced Mojmír to become a vassal of Arnulf. In 903, Luitpold held the title of a "dux Boemanorum", "Duke in Bohemia". He organised the Frankish defence against the Magyars under Grand Prince Árpád after invading Hungary, on 4 July 907 was killed east of Vienna in the Battle of Pressburg.