These were weighty influences in favour of a Celtic revival.

And they were all the more potent because, in or even before the period under discussion, the opening of the fifth century, a Celtic migration seems to have set in from the Irish coasts.

The details of this migration are unknown, and the few traces which survive of it are faint and not altogether intelligible.

The principal movement was that of the Scotti from North Ireland into Caledonia, with the result that, once settled there, or perhaps rather in the course of settling there, they went on to pillage Roman Britain.

There were also movements in the south, but apparently on a smaller scale and a more peaceful plan.[1] At a date given commonly as A.D.