In War of the Wolf, Edward marries Eadgyth to Sigtryggr (King of Northumbria).  I was doing some google fun, and it seems that the King of Northumbria was Sihtric and it was Athelstan who  married his sister to him after Edwards death.

Am I mistaken in this, or did you take some liberty in the book?

Always entertaining, please keep writing!

George Zazzi