The foundation legend of the Kingdom of the South Saxons is given by the Anglo-Saxon Chronicle, which states that in the year AD 477 Ælle arrived at a place called Cymenshore in three ships with his three sons.

However the archaeological evidence indicates that the principal area of settlement in the 5th century, for the South Saxons, has been identified as between the lower Ouse and Cuckmere rivers in East Sussex, based on the number of Anglo-Saxon cemeteries there.

[1] To the east of Pevensey, beyond the Saxon Shore fort of Anderitum, on the other side of the estuary and marsh and from there to the border with the Kingdom of Kent, lived a group known as the Haestingas.

[2] Not very much is known of the Haestingas but they were believed to be a separate people to the South Saxons; however, there is no archaeological evidence for occupation by Anglo-Saxons in that area of Sussex between the 5th and 8th centuries.

[1][10] Chevalier goes on to suggest that the Haestingas may have been of Frankish origin; however, other historians have rejected this, arguing that it is based on a misinterpretation of place-name evidence.

[14] The peace was shattered by the ascent of Mercian power; the chronicler Simeon of Durham records the defeat of the gens Hestingorum (the people of Hastings) by Offa of Mercia in 771.

[19] It has been suggested that the Haestingas were of Frankish origin, based on Watt being a sub-king to the South Saxons and there being a place-name of Watten in northern France.

Kent was the earliest Anglo-Saxon kingdom to be evangelized and it would have been at this time the simplified Christian burial was introduced.