| In 716 he set out on a missionary expedition to Frisia, intending to convert the Frisians by preaching to them in their own language, his own Anglo-Saxon language being similar to Frisian, but his efforts were frustrated by the war then being carried on between Charles Martel and Radbod, king of the Frisians. He returned to Nursling.In 723, Boniface felled the holy oak tree dedicated to Thor near the present-day town of Fritzlar in northern Hesse. He built a chapel from its wood at the site where today stands the cathedral of Fritzlar. St. Boniface |  |