Burkhard von Weisbriach was an ecclesiastical principality whose capital was the former city of what?
Archbishopric of Salzburg The Prince-Archbishopric of Salzburg (German: "Fürsterzbistum Salzburg" ) was an ecclesiastical principality and state of the Holy Roman Empire. It comprised the secular territory ruled by the Archbishops of Salzburg, as distinguished from the much larger Catholic diocese founded in 739 by Saint Boniface in the German stem duchy of Bavaria. The capital of the archbishopric was Salzburg, the former Roman city of "Iuvavum ".
Metropolis of Nicaea The Metropolis of Nicaea (Greek: Μητρόπολις Νικαίας ), was an ecclesiastical province (since the mid-4th century a metropolitan bishopric) of the Patriarchate of Constantinople in the city of Nicaea in the province of Bithynia (now Iznik in Turkey). A prestigious see due to its proximity to the Byzantine capital, Constantinople, and the location of two Ecumenical Councils in 325 and 787, the metropolitan see of Nicaea remained important until its conquest by the Ottoman Turks in 1331. The Christian element in the diocese diminished rapidly after that, with the flight of the Greek population and the Islamization of the remainder. As a result, the seat of the diocese was moved to Cius. The metropolis remained active until the population exchange between Greece and Turkey in the early 1920s. It remains a titular see of the Patriarchate of Constantinople as well as being, since the mid-15th century, a titular archbishopric of the Roman Catholic Church.