Pevensey Castle's inner bailey, showing a pile of catapult stones recovered from the moat. The castle’s impressive ruins stand on what was once a peninsula projecting from the Sussex coast. This naturally defensible site, first fortified by the Romans, was most famously the place where the Norman Conquest of England began, when William the Conqueror landed there on 28 September 1066. He built temporary defences at Pevensey, probably within the Roman fort, and later a great medieval castle developed inside its walls.