Pevensey is a village and civil parish in the Wealden district of East Sussex, England. The main village is located 5 miles (8 km) north-east of Eastbourne, one mile (1.6 km) inland from Pevensey Bay. The settlement of Pevensey Bay forms part of the parish. It was here that William the Conqueror first landed on and invaded England in 1066 after crossing the English Channel from Normandy, France.
The name Pevensey was first recorded in 947 as Pefenesea, meaning "River of [a man named] Pefen". It comes from the Anglo-Saxon personal name Pefen plus eã, meaning "river". This is probably a reference to the now largely silted-up marshes.
In the 290s the Romans built a fort at Pevensey, which they named Anderitum. In 471 Saxons attacked Pevensey and the fort was abandoned for centuries. When William the Conqueror invaded England in September 1066, he landed at Pevensey. The bay provided a safe haven for his fleet of 700 ships. The English army had been awaiting Duke William's arrival on the south coast all summer. With supplies running short King Harold allowed his soldiers to return home. When Harald Hardrada the king of Norway invaded northern England in late September, King Harold gathered his army and moved north to York, 250 miles away, to meet the invaders. William, meanwhile, moved his army and fleet to Hastings and built a castle while he awaited Harold and his army.
After the Battle of Hastings the Roman fort at Pevensey was occupied by the Normans. It was given to Robert, Count of Mortain (William's half brother). Robert de Mortain built his castle there. The castle was besieged several times during the 11th–13th centuries. Queen Elizabeth I ordered that it be demolished but the order was ignored. As late as 1942 small additions were made to the castle for the defence of Britain. It became a lookout over the channel for German aircraft during World War II. Today the castle is in the upkeep of English Heritage.