Power really has gone to your head! The kingdom of Alba has gathered a great deal of strength. It has support from the Gaelic lords of the west. See if you can gain more allies first, before you jump in at the deep end.
The Anglo-Danish rulers of Northumbria are in a weak position. They are suffering from attacks from both sides of the border. Join forces against your common enemy – Alba and the Anglo-Saxon kingdom to the south.
Sail south to Northumbria and take the lands of the Anglo-Danish settlers by force. You will gain land and the reputation of a cold-blooded, unscrupulous warrior.
Play a card.