The commencement of their conversion had been mainly the work of their brethren from Britain.
The monk Wilfred was followed in a few years by the Anglo-Saxon Willibrod.

It was he who destroyed the images of Woden in Walcheren, abolished his worship, and founded churches in North Holland.

Charles Martell rewarded him with extensive domains about Utrecht, together with many slaves and other chattels.

Soon afterwards he was consecrated Bishop of all the Frisians.

Thus rose the famous episcopate of Utrecht.