Tretower Castle is  in Wales that was founded as a motte and bailey castle whose son replaced the motte with a sheep keep that over times fell to ruins.
Tretower Castle (Welsh: Castell Tretwr) is a Grade I-listed ruined castle in the village of Tretower in the county of Powys, Wales. It was built around the beginning of the twelfth century as a motte and bailey castle and this was probably replaced mid-century by a stone shell keep. Probably around 1150, Picard's son, Roger Picard I, replaced the motte with a shell keep. The castle was enlarged in the early thirteenth century, but later fell into ruin. 
