|Location||(near) Dorchester on Thames|
The name of the tribe may be derived from an Old English word for "reliable" or "sure", (cf. German gewiss = "certain, sure"). The Anglo-Saxon Chronicle presents an eponymous ancestor figure, named Giwis. Eilert Ekwall proposed that the similarity in toponymy between the kingdoms of the Gewisse and Hwicce suggests a common origin.
The Gewisse captured Searobyrig in 552 and Beranbyrig from the Britons in 556. Birinus converted the Gewisse to Christianity in 636 by baptising their king Cynegils and establishing the Diocese of Dorchester. The Gewisse killed the three sons of Sæbert of Essex in about 620, defeated the Britons at the Battle of Peonnum in 660 and by 676 had sufficient control over what is now Hampshire to establish a see at Winchester.
The conquests by the royal house of Gewisse in the 7th and 8th centuries led to the establishment of the Kingdom of Wessex, and Bede treated the two names as interchangeable. It was only during the reign of Cædwalla (685/6 – 688) that the title "king of the Saxons" began to replace "king of the Gewisse". Barbara Yorke has suggested that it was Cædwalla's conquest of the Jutish province and the South Saxons that led to the need for a new title to distinguish the expanded realm from its predecessor. However, as there are no surviving documents to indicate how these people described themselves, the most that can be said is that by the time Bede was writing (early 8th century), the phrase "West Saxons" had come into use by scholars.
- Kirby, D.P. (2000), The earliest English kings, London: Routledge, ISBN 0-415-24210-X, retrieved 2009-06-07
- Leeds, E.T. (1954), "The Growth of Wessex", Oxoniensia, Oxford Architectural and Historical Society, LIX: 55–56, retrieved 6 October 2011
- Yorke, Barbara (1990), Kings and Kingdoms of Early Anglo-Saxon England, London: Routledge, ISBN 0-415-16639-X
- Yorke, Barbara (1995), Wessex in the Early Middle Ages, Continuum International Publishing Group, ISBN 0-7185-1856-X, retrieved 2009-06-07