Its use was really founded on practical convenience.

It was intermediate between the other two, and could be more or less comprehended both by the Northerner and the Southerner, though these could hardly understand each other.

The result was, naturally, that whilst the Northumbrian to the north of the Tweed was practically supreme, the Northumbrian to the south of it soon lost its position as a literary medium.

It thus becomes clear that we must, during the fifteenth century, treat the Northumbrian of England and that of Scotland separately.

Let us first investigate its position in England.
But before this can be appreciated, it is necessary to draw attention to the fact that the literature of the fifteenth century, in nearly all the text-books that treat of the subject, has been most unjustly underrated.