The main parts of the Low Countries were lightly populated until about
200 BC, when the climate and environment became more amenable to human habitation. Conditions remained favourable until 250 AD, and the region became densely populated. Fens below sea level were highly vulnerable to a
tidal bulge until great dams and sea walls were built as shown in the
North Sea flood of 1953. A series of
marine transgressions followed (in specialist academic literature called Dunkirk 0 through to Dunkirk IIIb) characterised by a rising water table and floods that left layers of clay on the land. The heaviest blow came with the "Dunkirk II transgression" that began in the 3rd century and continually worsened, leaving such low land uninhabitable, 350– 700
CE. People were forced to abandon their homes and emigrate. Archaeologists find evidence for this across the Rhine/Meuse delta (
Zeeland,
Brabant, parts of
South Holland and
Limburg);
Friesland;
Groningen;
Ostfriesland,
German Friesland and the
Weser/
Jade estuary; Across the Rhine/Meuse delta, the population became scant. Between the 5th and 7th centuries there were few centers of population there, and in the estuarine and peat areas no settlements have been found. The area would not be repopulated until the
Carolingian Era. Zones with river clay were so regularly deposited with
alluvial silt that habitation was almost impossible between the years 250 and 650.
Soil survey evidences and relative lack of human occupation artefacts leads scientists to theorise the
Netherlands was largely underwater between the mid-third-century and 1050. This more narrow geographic range of depopulation covers the third Dunkirk
Transgression period (alternatively suffixed
III). == See also ==