Medieval castles in Europe were built over a period of more than 500 years – from around 1000 AD to 1550 AD. Indeed they were built so well that many medieval castles (or at the very least their ruins) can still be seen today – a legacy that allows us the privilege of some truly tangible history.
Many people are fascinated by medieval castle history because so many castles are linked to major historical events including many medieval battles. Others find medieval castle design of interest as it saw dramatic changes over the years – from early motte and bailey castle design through to large concentric castle building. Indeed, medieval castle design probably reached its peak in the 14th century with the great castles of Wales built by King Edward I of England.
source – medieval-castle.com