Restormel is a very old castle. The original castle was built of wood shortly after the Norman Conquest. It is a motte and bailey construction of the Norman castles, but differs from most because its motte was cut into the rock. Around 1100 a gateway with a drawbridge was added. In the thirteenth century an almost perfect circular shaped shell keep was constructed out of stone. It was nearly 110 feet in diameter with walls 26 feet high and 8 ½ feet thick. The circular keep has battlements all around and a complete walk circling the interior.

The stone keep would have been an impressive residence and was probably built as a symbol of status and power. The large windows were built so that the occupants could look out over the countryside. The castle had a famous owner from 1337 to 1376. He was the Duke of Cornwall, Edward of Woodstock, who was also known as "The Black Prince".

The castle is located only a mile from Lostwithiel and is a peaceful place to visit. The original deer park is now a lovely park and picnic ground where one can rest, view the castle and dream of an earlier day.