Beginning around the 10th century, the ancient Normans introduced to Europe a style of wooden fort called the motte and bailey. Easily constructed, these forts were still very defensible. The motte was a hill, often man-made, with a wooden or stone keep on top of it. It overlooked the bailey, a large yard area surrounded by a wooden palisade. A typical motte and bailey fort included an outer ditch or moat for added defence.
The motte and bailey fort was an enclosed area, roughly oval in shape, that included a large, flat lower yard and a steep hill. For model building purposes, the easiest way to make the grounds is to use craft foam for the base. You can make the hill by stacking multiple layers of craft foam on one end of the yard and shaping the hill with a hot knife foam cutter. The hill would normally be very steep, almost cliff-like on the sides closest to the perimeter of the fort. The slope facing the yard would be gentler, accessible by men, horses and carts.
The motte and bailey historically would be surrounded by a wooden palisade to keep out intruders. You can use ice cream sticks or even thin dowels, sharpened at the top, to simulate the defences. Some palisades might include an interior walkway along the fence to allow defenders to shoot at enemies. The front entrance to the fort could be either a drawbridge or simple gates. You can use a hot knife foam cutter to carve a ditch around the fort, or use blue acrylic paints to create a moat.
Overlooking the bailey, the keep sat atop the motte, or hill. Depending on the wealth of the lord who built the fort, the keep could be made of wood or of stone. Its high perch made it almost inaccessible from three sides, and very defensible from its front. Either way, the keep would include sturdy gates and various defensive features, such as arrow slits or even grates for pouring hot oil on attackers. You can re-create a keep by either using ice cream sticks or thin balsa wood sheets for the walls and roof or battlements. Use paint for creating fine details.
Other buildings could be part of a motte and bailey fort, including stables, barracks and a granary or food storage. The largest such forts included entire towns. Additional buildings can be made out of balsa wood or ice cream sticks. When painting foam, do not use standard spray paint, as it will melt the foam. Use water-based acrylics or Krylon H2O latex spray paint. You can make your model more realistic with an application of craft soil or grass. Model railroad scale trees and lichen bushes make believable landscaping, and scale plastic people can bring life to your fortress complex.