Brighton’s earliest name was Bristelmestune, recorded in the Domesday Book. Although more than 40 variations have been documented, Brighthelmstone (or Brighthelmston) was the standard rendering between the 14th and 18th centuries.[5][6]

Brighton was originally an informal shortened form, first seen in 1660; it gradually supplanted the longer name, and was in general use from the late 18th century. Brighthelmstone was the town’s official name until 1810, though.[6] The name is of Saxon origin. Most scholars believe that it derives from Beorthelm + tūn—the homestead of Beorthelm, a common Saxon name associated with villages elsewhere in England.[6] The tūn element is common in Sussex, especially on the coast, although it occurs infrequently in combination with a personal name.[7] An alternative etymology taken from the Saxon words for “stony valley” is sometimes given but has less acceptance.[6] Brighthelm gives its name to, among other things, a church[8] and a pub in Brighton[9] and some halls of residence at the University of Sussex.[10]

The first settlement in the Brighton area was Whitehawk Camp, a Neolithic encampment on Whitehawk Hill which has been dated to between 3500 BC and 2700 BC.[14] It is one of six causewayed enclosures in Sussex. Archaeologists have only partially explored it, but have found numerous burial mounds, tools and bones, suggesting it was a place of some importance.[15] There was also a Bronze Age settlement at Coldean. Brythonic Celts arrived in Britain in the 7th century BC,[14] and an important Brythonic settlement existed at Hollingbury Camp on Hollingbury Hill. This Celtic Iron Age encampment dates from the 3rd or 2nd century BC and is circumscribed by substantial earthwork outer walls with a diameter of c. 1,000 feet (300 m). Cissbury Ring, roughly 10 miles (16 km) from Hollingbury, is suggested to have been the tribal “capital”.[16] Later, there was a Roman villa at Preston Village, a Roman road from London ran nearby, and much physical evidence of Roman occupation has been discovered locally.[14] From the 1st century AD, the Romans built a number of villas in Brighton and Romano-British Brythonic Celts formed farming settlements in the area.[17] After the Romans left in the early 4th century AD, the Brighton area returned to the control of the native Celts. Anglo-Saxons then invaded in the late 5th century AD, and the region became part of the Kingdom of Sussex, founded in 477 AD by king Ælle.[18]