The history of any place is affected, often dictated, by its geographical location, and there is no better example of this than the town of Seaford. Had it grown up a few miles further north, it would never have been more than a village and would probably have remained less important than neighbouring Alfriston which is sited next to a once navigable river. But men settled in Seaford because it was on the coast and on a river estuary and it is this which has shaped its history at every period since. Flint implements have been found in and around the town, indicating Stone Age occupation of the area, and part of a large Iron Age hill fort is still discernible on Seaford Head in spite of considerable cliff erosion. There was a substantial Roman villa at Eastbourne and a Roman burial ground on the present Seaford Head golf course. Roman funerary vessels and Roman coins have been found locally so it would seem that Seaford was inhabited periodically, if not constantly, by Ancient Britons right through to the Romano-British period. The first written evidence of Seaford comes from the Saxon occupation in the fifth century when Sefordt was mentioned in early chronicles inferring a ford near the sea or perhaps a fiord of the sea. An eighth-century transaction mentions a town as being Super fluvium Saforda or ‘on the river Saforda’, presumably the river Ouse which then flowed into the sea at Seaford. Although the town's earliest history must remain vague, the sea and the river Ouse are very real and we do know how nature used these two geographical features to set Seaford literally on the map. In fact, to understand Seaford's eminence in the Middle Ages and its political significance in the 18th century we simply have to look at the winds and tides in Seaford Bay. Although Seaford is on the south coast, it actually faces south-west so is at the mercy of the gales coming in directly from the Atlantic. Many centuries ago the tides and prevailing winds gradually built up a great shingle bank right across Seaford Bay from the cliffs at Meeching (Newhaven) to the cliffs at Seaford Head. As this barrier grew, the river Ouse was diverted eastwards until it drove its way out into the sea at possibly either the Buckle or at Splash Point under Seaford Head and the very low-lying area behind the bank was flooded and formed a natural harbour. It is difficult to picture this in the Seaford of today until one remembers that in Saxon times the cliff ends at Meeching and Seaford projected further out into the sea, so that the shingle barrier was further seaward than the present shoreline. A look at the conjectural map of the bay in that period superimposed over Seaford of the 1980s shows how the old river Ouse flowed inland, rounding the spurs and lapping into the ancient Ice Age valleys of Bishopstone, Hawth and Blatchington. Certainly this happened long before the Norman Conquest and we know that by the early 13th century Seaford was a Cinque Port and senior limb of the head port of Hastings, the other head ports at that time being Sandwich, Dover, Romney and Hythe. During its most prosperous period the port of Seaford gave employment in fishing, ship building, provisioning of ships and a two-way trade with the continent, importing wines and exporting wool from the large flocks of Downland sheep.
A busy port also needed defence so there was a fort to protect its entrance and presumably some form of local militia to man it. The entire maritime defence of the realm was in the hands of the Cinque Ports whose duty it was to provide a tally of ships and 'marines' proportionate to their respective status. It is known that in 1342 Seaford sent three ships to the French wars and in 1347 its official tally was five ships and 80 marines, so it is not difficult to picture a bustling port and a thriving populous town in the 14th century. In 1298, because it was a Cinque Port, Seaford was granted the right to send two members to parliament. This had a great influence on its political and social history over the next 500 years.