Northumbria And Cumbria

Northumbria once meant Northern England. However, in Poul Anderson's Mother Of Kings (New York, January 2003, first edition: September 2001), Eirik Blood-ax, ruling "Yorkish Northumbria" (p. 257), is at peace with "Northern Northumbia" (p. 259) which stretches to the Firth of Forth, thus well into what we call Scotland.

To the west and northwest of Yorkish Northumbria is the earldom of Cumbria, "...occupying, approximately, present-day Cumberland, Westmorland, and Lancashire."
-Poul Anderson, "Geographical Glossary" IN Mother Of Kings, pp. 607-611 AT p. 607.

In 1974, Cumberland and Westmorland were reunited as "Cumbria." I know this because I grew up in Cumberland and have lived in Lancashire since 1973 but there was no reason why Poul Anderson living in the US should have known it! Geography is perhaps my worst subject. This detail came to light only because I am rereading Mother Of Kings in such detail. Like probably most readers, I refer to the Geographical Glossary and Dramatis Personae list but do not read their every word or regard them as part of the text.