Aribo of Austria

Aribo (or Arbo) (c. 850 – 909) was the margrave (comes terminalis, "frontier count") of the March of Pannonia, from 871 until his death. In his day, the march orientalis corresponded to a front along the Danube from the Traungau to the Szombathely and Rába rivers and including the Vienna basin.
Aribo was originally appointed to succeed the brothers William and Engelschalk I after they died on campaign against Moravia. This has been used to support the hypothesis that he was a brother-in-law of the two margraves. Aribo maintained peace with Svatopluk of Moravia and it paid off when, in 882, the son of the late margrave Engelschalk, Engelschalk II, rebelled against him, claiming the rights to the march. The emperor Charles the Fat confirmed Aribo's position and Engelschalk turned to Arnulf of Carinthia, Aribo's southern neighbour, for support. Svatopluk, however, entered the Wilhelminer War on the side of Aribo and the emperor. In 884, peace returned to the marcha.
A sign of Aribo's strength after this was that he was unable to be unseated by Arnulf when the latter succeeded to the German throne in 887. In 893, Arnulf appointed Engelschalk II to a portion of the Pannonian march over Aribo's head. Aribo never reconciled with Arnulf after the Wilhelimner War and his contacts with the Moravians were kept secure. After his falling out, his son Isanrich got Moravian support against Arnulf. Aribo's descendants formed the Aribonid family. They held the Archbishopric of Salzburg in the 10th century, but were pushed out of power in the Duchy of Bavaria by the Liutpoldings.