939 York controlled by vikings again

coin of  Olaf Guthfrithsson - A raven with outstrecthed wings
England
Olaf Guthfrithsson conquered York and controlled it until 943.
Denmark
Battles in Denmark between various factions for the control of Hedeby.
Hedeby Coins with ship motif from the 9th century

Brittany, Battle of Trans-la-Fôret The battle happened on August 1, 939 between the Viking occupation forces and the Bretons, led by the combined armies of Alan II, Count Hugh II of Maine, and Judicael Berengar.

The Bretons were victorious; the victory at Trans-la-Forêt freed Brittany of Viking occupation, and led to the establishment of the Duchy of Brittany under Alan II, the Duke of Brittany. After 3 years fighting the Scandinavian vikings were finally repelled and driven out of Brittany.