Sussex is one of the oldest place names still in everyday use in England, and also one of the most transparent, once you know what you are looking at. It comes from the Old English Sūþseaxe, meaning simply 'South Saxons'. Strip away a thousand years of pronunciation and spelling drift, and the name is still doing exactly the job it always did: telling you who lived there, and where.
The South Saxons were one of several Saxon and Anglian groups who settled in Britain from the fifth century onward, as Roman administration collapsed and new arrivals from the North Sea coast of what is now Germany, Denmark and the Netherlands established themselves across eastern and southern Britain. Bede, writing in the early eighth century, describes distinct Saxon peoples occupying the south of the island—the South Saxons around what is now West and East Sussex, the West Saxons further west, and the East Saxons in the Thames estuary region that still carries their name as Essex.
It is worth being honest about how thin the written evidence for this period actually is. We are not dealing with detailed contemporary records of a 'Kingdom of Sussex' with clear borders and a documented founding date. Much of what we know comes from later sources—Bede writing centuries afterward, place-name evidence, archaeology, and the Anglo-Saxon Chronicle, itself compiled well after many of the events it describes. Historians broadly agree that a South Saxon kingdom existed and was politically significant in the sixth to eighth centuries, but the details of its earliest history are reconstructed from fragments, not read off a single reliable page.
What is more solid is the linguistic trail. 'Seaxe' (Saxons) plus 'suþ' (south) gives Sūþseaxe, which Latin-writing clerks and later scribes gradually compressed and respelled—Sussexe, Sussex—as English itself changed shape over the medieval period. The same pattern explains Essex (East Saxons), Wessex (West Saxons, though this survives only as a historical and cultural name rather than a modern county), and Middlesex (Middle Saxons). Suffolk and Norfolk follow a parallel logic from a different tribal group, meaning 'south folk' and 'north folk' of the East Angles.
The South Saxon kingdom was absorbed into the growing kingdom of Wessex by the late eighth century, long before 'England' existed as a single political idea—that unification was still centuries away, and is its own story. But the regional name survived every later change of ruler, language and administration: Norman conquest, medieval county boundaries, Tudor administration, and the modern division into West Sussex and East Sussex in 1974. Few identities in England have proved as durable as this one, precisely because it never claimed to be more than a description: the land of the people from the south.
None of this requires embellishment to be interesting. The real story—migration, an ill-recorded early kingdom, a name that outlived the people who first used it—is more useful, and more honest, than any invented pageantry. That is the standard this publication is trying to hold itself to: understand what actually happened, say clearly where the evidence runs out, and leave the costume drama to someone else.