natural spring in Geismar, called Heilgenbron; the name "Geismar" (possibly "energetic pool") itself may be derived from that spring. The village of , now a part of Gudensberg near Fritzlar and less than ten miles from Geismar, was likely an ancient religious center: the basalt outcrop of Gudensberg is named for Wodan, and there is a two-meter tall quartz megalith called the Wotanstein in the center of the village. Büraburg itself contained a Christian settlement before Boniface. The St. Brigida church was dated to the time of the Hiberno-Scottish mission by Joseph Vonderau, a Fulda archeologist who excavated Büraburg in the 1920s. According to Wand, the church must have been founded later; he states it probably served the Frankish fortress whose construction he dated c. 690. Though one scholar considers that Wand's later dating is correct and that there is no reason to assume the church was already named for St. Brigid, recent scholarship suggests perhaps Vonderau was correct in assuming the Hiberno-Scottish background. For instance, after renovations from 2002-2006, pieces of wood were found in the chancel arch that dated back to between the mid-sixth century and 667/668. This may mean that the church predates even the mission of Saint Kilian, who may have preached in the area in the 680s and was killed in Thuringia in 689—or it may mean that older wood was used to construct the church. Wand's excavations (1969-1996) revealed a monastic complex whose oldest layer contains a cistern lined with stone; one of those stones featured an inscription of the Benedictine cross. The complex could have housed an abbot with up to six monks. Excavations have shown traces of at least sixty buildings (not all from the same time period). John-Henry Clay considers it likely that the church was indeed Hiberno-Scottish and dates from the earliest fortification, using wood from some nearby building. The connection between Kilian and Boniface is not unique; in Wurzburg Boniface promoted Kilian's cult, and he may have used the cistern in Büraburg as a baptismal font, continuing missionary work that already started before he came to the area. Donar Oak and bishopric In 723 AD the Anglo-Saxon missionary Saint Boniface arrived in the area on his mission to convert the central and northern German tribes to Christianity. Seeking to demonstrate the superiority of Christianity, he and his followers felled a sacred oak dedicated to the god Donar (Thor) by