2. Short history of the discussion on the occupation during the 4th century
The idea of an Anglo-Saxon invasion originates in the early days of terp archaeology. Already in 1906, the curator of the Frisian Museum during the first half of the 20th century, P.C.J.A. Boeles, brought forward the idea of an Anglo-Saxon invasion. His ideas were based on his recognition of a new material culture, in particular pottery and cruciform brooches. Boeles believed that the Anglo-Saxons had invaded a populated area and had absorbed the Frisian population that remained after their attacks, thus forming a new Anglo-Frisian population. Despite strong opposition, Boeles stayed with his views (cf. Bazelmans 2002). In the second edition of his magnum opus Friesland tot de elfde eeuw (Friesland until the 11th century) of 1951 (205ff), he once more summarized the discussion and his arguments, using the preliminary publication of the excavations in the terp of Ezinge by Van Giffen (1936) as a source of supporting evidence for his theory.
From finds in Frisian terps, it had become clear to Boeles that the pottery of the Frisians of the Roman Iron Age was never found together with Anglo-Saxon pottery and that typical Anglo-Saxon cemeteries (with Anglo-Saxon pottery and cruciform brooches) were introduced in the 5th century. In Ezinge, a loamy ash layer was reported to cover Roman Iron Age houses. Buildings above the burnt layer were small, Anglo-Saxon houses with sunken huts. Anglo-Saxon pottery was common in and around these buildings. This was interpreted by both Boeles and Van Giffen as an indication that there had been a hostile take-over by the Anglo-Saxons. Boeles’ arguments did not convince Frisian nationalists, nor scholars who thought that migration was not the best explanation of changes in material culture. The debate continued until well into the 1970s (Bazelmans 2002). One of the last discussants was Waterbolk, who recognized that many terp settlements had been abandoned from the 3rd century onwards. However, while ignoring the 4th century, he inferred from the many finds from the 5th-7th centuries that habitation in Friesland in the Migration Period had been continuous (Waterbolk 1979, 17).
The discussion on the habitation of the terp region during the 4th century was rekindled in the 1990s by new evidence that supported Boeles’ idea of an Anglo-Saxon immigration, though not of an aggressive invasion. It now had become clear that the area had been abandoned before these immigrants arrived. The new evidence came from the excavations in Wijnaldum (1991-1993; Gerrets & De Koning 1999) and from the study of indigenous handmade pottery by Taayke (1996). From the virtual absence of 4th century pottery, Taayke concluded that the terp area was gradually abandoned in the course of the 3rd century AD and that habitation had come to an end in the 4th century almost everywhere. He described this process under the somewhat ironic heading Die Entfriesung der nördlichen Niederlande (Taayke 1996, V, 193). However, from the occurrence of some new types of pottery Taayke argues that a small population probably remained on some terps in Groningen, in particular at Ezinge (Taayke 1996, III, 55; V, 195ff).