The hiatus of the 4th century AD in the terp region During the 20th century, the population history of the terp region of the northern Netherlands during the Migration Period was hotly debated. The new idea that the different material culture of the 5th century, compared to the Roman Iron Age, indicates immigration by Anglo-Saxons was not accepted by everyone, on nationalistic but also on theoretical grounds, since there is no one-to-one relation between material culture and ethnic identity. This article summarizes and examines arguments and evidence. Pottery research supports the idea that most of the terp region was not inhabited during the 4th century, with some exceptions such as Ezinge in the province of Groningen, and Jelsum and Marssum in the province of Friesland. The hiatus is especially clear when we compare coastal pottery to the pottery of the inland Pleistocene region, where habitation and the development of pottery style continued without interruption. Overseeing all the evidence, it seems that the terp region, especially the eastern part, the province of Groningen, was part of a socio-cultural network that extended far into northwestern Germany. Where habitation was uninterrupted within this network, in northwestern Germany, northern Drenthe, and in a small number of settlements in the terp region, pottery style developed in largely the same way, often with decoration and shapes in the style that is traditionally called Anglo-Saxon. Newcomers from the Anglo-Saxon regions brought their own pottery and other objects in the 5th century, but their pottery resembled local pottery. The socio-cultural network also appears from burial ritual. The isolated burials and single bones from before the 4th century clearly differ from the cemeteries with inhumations and cremations that appear in the 5th century. However, already in the 3rd century, there are indications of changing traditions. Small cemeteries from that period are found near houses in several settlements in the northern Netherlands and ...