Menne KOSIAN
(National Service for Archaeology, Cultural Landscape and Built Heritage, Amersfoort, The Neteherlands)
In the 14th century the bishop of Utrecht decided to strengthen the Southern border of his lands east of the river IJssel against the invasions by the duke of Gelderland. This was done by erecting a ‘landweer’, a defence dike from Deventer to Holten. East of Holten this dike disappeared into the moors, which were impenetrable and so a natural defence.
The common form was an embankment, of about a man’s height, planted with thorns and thick bushes on the outside, facing the enemy, and with a moat at its base. At several point there were openings to let traffic trough, defended by fortified house or small castles.
This landweer was used till 1528, when Charlemain obtained power over both Gelderland and Utrecht, and the defence systems became obsolete. Using several ancient maps, in combination with modern altitude data, it is possible to retrace the course of this landweer. And interesting aspect is that around the monastery Ter Hunnepe this landweer seems to be defending Gelderland, with the moat on the inside of the dike, according to the map by Johan van Wijck from 1668. Closer inspection, however, indicates that in this case the moat was something to be defended; it was a millpond supply for one of Deventers watermills. During the workshop I can show both the reconstructed course of the landweer as the detailed course around the Ter Hunnepe monastery by superimposing several period-maps.
Keywords: old maps in modern GIS, specific function to form of defence dike.