from the East Frankish kings. Though in 911 he participated in the election of King Conrad I of Germany in 911; in Conrad's conflict with Erchanger of Swabia he backed his Swabian uncle and later challenged Conrad's Saxon successor, King Henry the Fowler. The dispute was only temporarily settled when in 913 Arnulf's widow mother Cunigunda married King Conrad. In 916 Conrad's forces invaded Bavaria, attacking and pillaging Regensburg. These attacks drove Arnulf into exile with his former enemies in Hungary. In September, the king convoked a church council in Hohenaltheim, attended by the Bavarian episcopate, which summoned Arnulf and his younger brother Berthold on the grounds of excommunication at Regensburg on 1 November. It is more than likely that Arnulf and his family never appeared at the convocation, or that the council meeting was never held. As a result, they remained exiled among the Hungarians. In January 917, King Conrad, angered at the situation, called for the execution of his rebellious Swabian brother-in-law, Erchanger and his brother Berthold, giving Arnulf more pause for concern. In 919, the death of Conrad I allowed Arnulf to return to Bavaria and expel the king's forces. Conrad I being childless, the throne was open to Arnulf, again. On his return, according to the Annales iuvavenses, in 920, Baiuarii sponte se reddiderunt Arnolfo duci et regnare ei fecerunt in regno teutonicorum ("the Bavarians freely submitted themselves to Duke Arnulf and asked him to reign within the realm of the Germans"). The 919 ascension of Henry the Fowler would bring forth a battle for the throne; however, whether the Bavarians, with some other East Franks, actually elected Arnulf anti-king in opposition to Henry has not been conclusively established. In any case, Arnulf's "reign" was short-lived; King Henry I turned out to be a strong opponent and defeated him in two campaigns in 921. When Arnulf was besieged by Henry in Regensburg, the duke entered into peace negotiations and recognized the sovereignty of the German king. King Henry confirmed Arnulf's autonomous rule over Bavaria, including the right of investiture and several important regalia, in return for Arnulf's renunciation of his royal claim. Later years Arnulf accompanied King Henry I on his 928 campaign against Duke Wenceslaus of Bohemia. In 935 he launched an attack against King Hugh of Provence to obtain the Iron Crown of Lombardy for his eldest son Eberhard, which only resulted in defeat.