Although the northern provinces had an as yet subordinate position in the aggregate economy of the Habsburg Netherlands, let alone in the entire Habsburg empire, they possessed economic features that set them apart from the rest of Europe, and presented them with opportunities that did not exist elsewhere. Unlike other parts of Europe these lands had not been ravaged severely by the plague of the 14th century, though like elsewhere that catastrophe contributed to scarcity of labor in the 15th century. The region also faced catastrophe of an ecological nature: the low-lying area was yet insufficiently protected against the sea and was repeatedly subjected to major flooding, of which the St. Elizabeth's flood (1421) was only one, although outstanding example. This resulted in a major permanent loss of arable land. In addition, the land in the maritime provinces consisted mostly of peat bogs, which form poor land for agriculture, and were at the time extensively exploited for the fuel peat. This resulted again in extensive permanent loss of arable land. Because of these losses many people were driven from the land and forced to seek employment in urban centers. This caused a degree of urbanization even larger than that in Flanders, but also a labor supply for non-agricultural purposes that was more elastic than elsewhere in Europe.