Ancient and medieval Frisia was an ethno-linguistic entity far larger than the modern province of Friesland, Netherlands. Water outweighed land over its geographical extent, and its marginal political status, unconquered by the Romans and without the feudal social structure typical of the Middle Ages, made Frisia independent and strange to its would-be conquerors. This article opens with Frisia’s encounters with Rome, and its portrayal in Latin texts as a wretched land of water-logged beggars, ultimately unworthy of annexation. Next, the early medieval conflict between the Frisians and the Danes/Geats, featured in Beowulf and other epic fragments, is examined. Pagan Frisia became of interest during Frankish territorial expansion via a combination of missionary activity and warfare from the seventh century onward. The vitae of saints Willibrord, Boniface, Liudger and Wulfram provide insights into the conversion of Frisia, and the resistance to Christianity and Frankish overlordship of Radbod, its last Pagan king. It is contended that the watery terrain and distinctive culture of Frisia (pastoralism, seafaring, Pagan religion) as noted in ancient and medieval texts rendered it “other” to politically centralized entities such as Rome and Francia. Frisia was eventually tamed and integrated through conversion to Christianity and absorption into Francia after the death of Radbod.