Their chief town was at Bebbanburh, now Bamborough, which Ida "timbered, and betyned it with a hedge." Next in geographical order stood the people of Deira, or Yorkshire, who occupied the rich agricultural valley of the Ouse, the fertile alluvial tract of Holderness, and the bleak coast-line from Tyne to Humber.

Whether they conquered the Roman capital of York, or whether it made terms with the invaders, we do not know; but it is not mentioned as the chief town of the English kings before the days of Eadwine, under whom the two Northumbrian chieftainships were united into a single kingdom.

However, as Eadwine assumed some of the imperial Roman trappings, it seems not unlikely that a portion at least of the Romanised population survived the conquest.

The two principalities probably spread back politically in most places as far as the watershed which separates the basins of the German Ocean and the Irish Sea; but the English population seems to have lived mainly along the coast or in the fertile valley of the Ouse and its tributaries; for Elmet and Loidis, two Welsh principalities, long held out in the Leeds district, and the people of the dales and the inland parts, as we shall see reason hereafter to conclude, even now show evident marks of Celtic descent.

Together the two chieftainships were generally known by the name of Northumberland, now confined to their central portion; but it must never be forgotten that the Lothians, which at present form part of modern Scotland, were originally a portion of this early English kingdom, and are still, perhaps, more purely English in blood and speech than any other district in our island.
From Humber to the Wash was occupied by a second English colony, the men of Lincolnshire, divided into three minor tribes, one of which, the Gainas, has left its name to Gainsborough.