The English bishops were thus at first royal chaplains, and their diocese was naturally nothing but the kingdom.
In this way realms which are all but forgotten are commemorated in the limits of existing sees.

That of Rochester represented till of late an obscure kingdom of West Kent, and the frontier of the original kingdom of Mercia may be recovered by following the map of the ancient bishopric of Lichfield.

In adding many sees to those he found Theodore was careful to make their dioceses co-extensive with existing tribal demarcations.

But he soon passed from this extension of the episcopate to its organization.
In his arrangement of dioceses, and the way in which he grouped them round the see of Canterbury, in his national synods and ecclesiastical canons, Theodore did unconsciously a political work.

The old divisions of kingdoms and tribes about him, divisions which had sprung for the most part from mere accidents of the conquest, were now fast breaking down.
The smaller states were by this time practically absorbed by the three larger ones, and of these three Mercia and Wessex were compelled to bow to the superiority of Northumbria.