Büraburg, a prominent hill with historic significance, overlooking the Eder river near the town of Fritzlar in northern Hesse. In 723 A.D., the Anglo-Saxon missionary Winfrid -- later called St. Boniface, apostle of the Germans -- arrived in the area on his mission to convert the central and northern German tribes to Christianity and made Büraburg, then a fortified Frankish settlement, his temporary base. Seeking to demonstrate the superiority of the Christian god over the Germanic gods, he and his followers felled a sacred oak dedicated to Thor by the local tribe of the Chatten/Chatti. When Thor failed to hurl a lightning bolt at Boniface and his companions, as the locals had expected, they agreed to be baptized. This event thus marked the beginning of the Christianization of the Germans.

Using the wood of the oak, Boniface erected a small chapel at a site nearby in what soon became the important religious, intellectual and trade center of Fritzlar. Boniface subsequently (742) elevated Büraburg to a bishopric, the first in Germany east of the Roman Limes, but after the death of the first and only bishop, Witta, in 748 the bishopric was incorporated by Lullus, Boniface's successor as archbishop of Mainz, into his own diocese. From 747 to 786 Büraburg was administered by an auxiliary bishop, Meginoz, but this post was not filled again after Meginoz' death.

Excavations have unearthed extensive fortifications from the 7th and 8th century A.D. on the hill top, remnants of a major settlement at this important site located where Frankish and Saxon territories then bordered each other. During the Saxon wars of Charlemagne, it was an important fortified base of the Franks, but with the final submission of the Saxons in 804 it lost its military significance. Today, a small parish church stands at the site, containing parts of the original church building.