While his predecessor,
Aldgisl, had welcomed
Christianity into his realm, Radbod attempted to extirpate the religion and gain independence from the kingdom of the Franks. In 689, however, Radbod was defeated by
Pepin of Herstal in the battle of
Dorestad and compelled to cede Frisia Citerior (Nearer Frisia, from the
Scheldt to the
Vlie) to the
Franks. Between 690 and 692,
Utrecht fell into the hands of Pepin. This gave the Franks control of important trade routes on the
Rhine to the
North Sea. Some sources say that, following this defeat, Radbod retreated, in 697, to the island of
Heligoland. Others say he retreated to the part of the Netherlands that is still known as Friesland. Around this time there was an Archbishopric or
bishopric of the Frisians founded for
Willibrord and a marriage was held between
Grimoald the Younger, the oldest son of Pepin, and
Thiadsvind, the daughter of Radbod in 711. On Pepin's death in 714, Radbod took the initiative again. He forced
Saint Willibrord and his monks to flee and advanced as far as
Cologne, where he defeated
Charles Martel, Pepin's natural son, in 716. Eventually, however, Charles prevailed and compelled the Frisians to submit. Radbod died in 719, but for some years his successors struggled against the Frankish power. As an example of how powerful King Radbod still was at the end of his life, the news that he was engaged in assembling an army was reportedly enough to fill the Frankish kingdom with fear and trembling. == Relation with Christianity ==