Sussex was home to some of Europe's earliest known hominids ("Homo heidelbergensis"), whose remains at Boxgrove have been dated to 500,000 years ago. Sussex played a key role in the Roman conquest of Britain, with some of the earliest significant signs of a Roman presence in Britain. Local chieftains allied with Rome, resulting in Cogidubnus being given a client kingdom centred on Chichester. The kingdom of Sussex was founded in the aftermath of the Roman withdrawal from Britain. According to legend, it was founded by Ælle, King of Sussex, in AD 477. Around 827, it was annexed by the kingdom of Wessex and subsequently became a county of England. Sussex played a key role in the Norman conquest of England when in 1066, William, Duke of Normandy, landed at Pevensey and fought the decisive Battle of Hastings.