About 670, the later Franconian Saint Kilian was preaching in Hallstadt and almost 50 years later Saint Boniface tried to convert Hallstadt’s Germans. Eventually, sometime between 741 and 747, the town was first named as "Halazestat im Radensgove" in a document issued by the Frankish Dukes Karlmann and Pepin the Short, and in 793, Charlemagne approved his father Pepin’s donations to the Würzburg Bishop Berwolf, among which was "Halazestat". From 794 to 820, the Hallstadt Church of St. Kilian was built as one of Charlemagne’s 14 Slavic churches ("Slavenkirchen"), and in 805, Hallstadt became Charlemagne’s royal court after years earlier (793) he had spent the night here.