Boniface  attempted, in the place called Gaesmere, while the servants of God stood by his side, to fell a certain oak of extraordinary size, which is called, by an old name of the pagans, the Oak of Thor. And when in the strength of his steadfast heart he had cut the lower notch, there was present a great multitude of pagans, who in their souls were earnestly cursing the enemy of their gods. But when the fore side of the tree was notched only a little, suddenly the oak’s vast bulk, driven by a blast from above, crashed to the ground, shivering its crown of branches as it fell; and, as if by the gracious compensation of the Most High, it was also burst into four parts, and four trunks of huge size, equal in length, were seen, unwrought by the brethren who stood by. At this sight the pagans who before had cursed now, on the contrary, believed, and blessed the Lord, and put away their former reviling. 

–Life of Boniface, Missionary to the Germans