Although a chair of prehistory had been established at the University of Liège in 1926, departments of national archaeology were not created at Ghent and bilingual Louvain until the end of the 1940s. The new branches were integrated into existing institutes for archaeology and the history of art, and it was only at Ghent that there was also a connection to the Department of History.

Between the two world wars, field research generally began reaching a level comparable to that in neighboring countries. Jacques Breuer, director of the State Service for Excavations and trained in the Netherlands, introduced the open-area and quadrant methods of excavation and created the journal Archéologie to provide rapid publication of field data. There was, however, one fundamental obstacle to archaeology’s development—the absence of legislation to regulate the protection and excavation of sites. As late as 1972, Jozef Mertens, research director under Breuer, could proclaim with a sense of irony that Belgium was one of the few countries in the world without illegal archaeological activities, and it would stay that way for another two decades. The handful of professional archaeologists working for the State Service and at universities and self-educated amateurs were unable to cope with professional looters, development projects, and growing population density. At Court-Saint-Etienne, only a few of the original sixty or more large Hallstatt burial mounds remained intact for archaeological investigation, and during large-scale construction activities in Brussels in the 1950s, which cut through the city’s medieval center, not a single archaeological site or artifact was reported.

The three decades after World War II were very productive in terms of both fieldwork and interpretation. Syntheses of variable quality were published for different periods, and in those published on more recent periods, the origin of the language frontier was always an issue. At Ghent, the historian Hubert Van De Weerd formed the first generation of Flemish archaeologists, and one of these, Sigfried J. De Laet, was appointed to the Chair of National Pre- and Protohistory. Jozef R. Mertens, research director at the State Service for Excavations under Breuer, was appointed to the university in Louvain. Jean de Heinzelin resumed the Museum of Natural History’s historic interest in Paleolithic prehistory, and the museum’s excavation of the Upper Paleolithic open-air site at Maisières is a landmark for its detailed stratigraphic recording and elaborate paleoenvironmental reconstructions. All of these researchers were convinced of the discipline’s need to both rethink its aims and utilize new methods, particularly those for environmental reconstruction.

In an impressive fieldwork record ranging from Iron Age to medieval sites, Mertens changed the nature of provincial Roman archaeology, redefining it as a social geography involving such issues as settlement systems, land partitioning, and transportation networks. De Laet was concerned with the nature of archaeology in general and was well aware of the changes in this respect that were taking place internationally. He is the only Belgian archaeologist to have published a major theoretical reflection, in which he expressed severe criticisms of traditional archaeology, its unwarranted ethnic interpretations, and the danger of possible political misuse. At the same time, however, he was strongly opposed to the nomothetic (positivist search for the laws of human history) aims of the new archaeology and to anthropological archaeology.

The State Service for Excavations, still attached to the Royal Museum for Art and History, became an independent scientific institution in 1963, and a parallel National Centre for Archaeological Research was established for documentation. During the 1960s, the latter published exhaustive inventories of archaeological sites in Belgium, and De Laet created the journal Helinium to publish contributions on the archaeology of Belgium, the Netherlands, and Luxembourg. Some of Belgium’s most important sites were excavated during this period: Roman settlements such as the vici of Liberchies, Blicqui, Elewijt, and Velzeke and the fortified site at Oudenburg on the North Sea coast; la tène oppida (fortified cities) at the Kemmelberg and Buzenol sites and a number of protohistoric burial sites in the Campine region; and