In the wet regions in the north of the Netherlands, people lived on man-made hills from late prehistoric times. In Groningen these mounds were called wierden, while in Friesland they were known as terpen. Many of these hills were levelled in the 19th century, to enable their fertile soil to be used for agriculture. These activities turned up numerous objects, frequently spanning over a thousand years for each individual terp. The finds originating from a terp in Loppersum, Groningen, for instance, consist of generations of pottery and jewellery, spanning the period from the prehistoric Iron Age right up to the Middle Ages. This Saxon pottery urn was made by hand around AD 400.