Saint Kilian
During Christianization, Bishop Corbinian laid the foundations for the later Diocese of Freising before 724; Saint Kilian in the 7th century had been a missionary of the Franconian territory in the north, then ruled by the Dukes of Thuringia, where Boniface founded the Diocese of Würzburg in 742. In the adjacent Alamannic (Swabian) lands west of the Lech river, Augsburg was a bishop's seat. When Boniface established the Diocese of Passau in 739, he could already build on local Early Christian traditions. In the south, Saint Rupert had founded in 696 the Diocese of Salzburg, probably after he had baptized Duke Theodo of Bavaria at his court in Regensburg, becoming the "Apostle of Bavaria". In 798 Pope Leo III created the Bavarian ecclesiastical province with Salzburg as metropolitan seat and Regensburg, Passau, Freising and Säben (later Brixen) as suffragan dioceses.