From September 1939 a more easterly Main Defence Line (MDL) was constructed. This second main defensive position had a northern part formed by the Grebbelinie (Grebbe line), located at the foothills of the Utrechtse Heuvelrug, an Ice Age moraine between Lake IJssel and the Lower Rhine. It was dug on instigation of the commander of the Field Army Lieutenant-General Jan Joseph Godfried baron van Voorst tot Voorst.Amersfoort (2005), p. 87 This line was extended by a southern part: the Peel-Raamstelling (Peel-Raam Position), located between the Maas and the Belgian border along the Peel Marshes and the Raam River, as ordered by the Dutch Commander in Chief, General Izaak H. Reijnders. In the south the intention was to delay the Germans as much as possible to cover a French advance. Fourth and Second Army Corps were positioned at the Grebbe Line; Third Army Corps were stationed at the Peel-Raam Position with the Light Division behind it to cover its southern flank. Brigade A and B were positioned between the Lower Rhine and the Maas. First Army Corps was a strategic reserve in the Fortress Holland, the southern perimeter of which was manned by another ten battalions and the eastern by six battalions.De Jong (1969b), p. 360 All these lines were reinforced by pillboxes.
