Map of Frisia in King Radbod’s time, 8th century. Page URL: https://commons.wikimedia.org/wiki/File:Frisia_716-la.svg
Attribution: Frankish_Empire_481_to_814-fr.svg: Sémhur, Eric.dane 800nc ex leg.jpg: RACM & TNO derivative work: Richardprins [CC BY-SA 3.0] River names added by J. Sytsema.