A church probably already existed at Ossiach, when Count Ozi about 1024 established the Benedictine abbey, the first in the medieval Duchy of Carinthia. The first monks probably descended from Niederaltaich Abbey in Bavaria. Ozi's son Poppo succeeded in removing the proprietary monastery from the influence of the Salzburg archbishops and to affiliate it with the Patriarchate of Aquileia, confirmed by Emperor Conrad II in 1028. Upon the extinction of the Styrian Otakars in 1192, the "Vogtei" of Ossiach according to the Georgenberg Pact passed to the Austrian House of Babenberg. In 1282 it finally fell to the Habsburgs.