We must also certainly include, if not Oxfordshire, at any rate the city of Oxford.
This is by far the most important group of counties, as it was the East Midland that finally prevailed over the rest, and was at last accepted as a standard, thus rising from the position of a dialect to be the language of the Empire.

The Midland prevailed over the Northern and Southern dialects because it was intermediate between them, and so helped to interpret between North and South; and the East Midland prevailed over the Western because it contained within its area all three of the chief literary centres, namely, Oxford, Cambridge, and London.

It follows from this that the Old Mercian dialect is of greater interest than either the Northumbrian or Anglo-Saxon.
Unfortunately, the amount of extant Old Mercian, before the Conquest, is not very large, and it is only of late years that the MSS.
containing it have been rightly understood.

Practically, the study of it dates only from 1885, when Dr Sweet published his _Oldest English Texts_.
But there is more Mercian to be found than was at first suspected; and it is desirable to consider this question.
An important discovery was that the language of the oldest Glossaries seems to be Mercian.

We have extant no less than four Glossaries in MSS.