937, the alliance was out in the open. That autumn, Constantin marched south. With him rode Owain, the King of Strathclyde. Meanwhile, at the head of an immense war-fleet, Olaf made the crossing from Ireland to join them. The combined armies of the three leaders, two of them the most powerful kings in Britain after Athelstan himself, and the third a notorious warlord, represented a potentially mortal threat to the nascent English realm.
