The Romans, having left in approximately the year 400, were followed in the year 477 by Ella. Ella arrived with her three sons and created the land of the South Saxons, with the capital being Selsey.
In 680 Wilfrid arrived - bringing with him Christianity. He became our first Bishop, being followed by another 22. William, having landed in Hastings decided to move the See to Chichester. Legend has it that the Cathedral in Selsey was washed out to sea. The parish church was originally at Norton but between 1864 and 1866 the Nave was moved to the present position of St Peter’s. The chancel was left behind and is now known as St Wilfrid’s Chapel.The peninsula was once an island with a ferry. The ferryman was paid, in 1661, four bushels of barley and was allowed to collect a halfpenny from each traveller. The causeway was completed in 1809 and from 1897 to 1935 Selsey had its own light railway, the Selsey Tram. Some of the carriages can be seen at East Beach where they have been converted into residences.

During WWI a Listening Post was built at East Beach to provide an early warning of approaching zepplins. The structure is an acoustic mirror built of concrete and shaped like a dish. It is still at East Beach in what is now a Grade 2 listed building.
During May 1943 RAF Selsey, which was situated at Church Norton, was established as an advanced landing ground. During the invasion it played an important part in the air cover of the beaches. A spitfire from RAF Selsey was responsible for shooting down the first German aircraft on D Day.
Prior to the D Day invasion the pre-fabricated Mulberry Harbours were stored in Selsey. The sections that were sunk off Selsey are frequently visited by divers.