Within the British Isles the period between the departure of the Romans (c. 400) and the coming of the Vikings (c. 800) was marked by the interaction of four distinct cultures, British, Pictish, Irish and Anglo-Saxon. At the beginning of the period British culture (the culture of the P-Celtic-speaking peoples) was dominant over most of the island of Britain south of the Forth. Much of this culture in what is now southern England and South Wales was heavily Romanised. Roman towns and general organisation survived well into the fifth century. Further north, for example in the territory of the Votadini between the Forth and the Tweed, the extent of Roman influence had been much less. North of the Forth, the culture of the Picts (originally known to the Romans first as Caledonii and then from the fourth century as Picti) was dominant. We know less about the Picts than any of the other three major cultures of the British Isles but place-names and other evidence indicate that there were two main groups, the southern Picts south of the Mounth and northern Picts north of the Mounth and in Shetland and Orkney. During the Roman centuries the Q-Celtic-speaking cultures of Ireland had been placed in a position of relative isolation, which was being broken down by the arrival of Christian missionaries from Britain and the continent.