The transition of York from Roman-British to Anglian control sometime in the fifth century was likely marked by violence though the exact circumstances are unknown. The Anglian kingdom of Deira was centred on York and the Vale of York. Eboracum became Eoforwic; Latin was replaced by Old English; the Roman street plan survived in the city's bones. This transition, however it occurred, set the stage for York's role as the capital of Northumbria.
The size of the opposing forces is not recorded in the surviving sources.
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