The following events give an indication that the Bretons initially allied themselves with these strangers in attacks on the Franks: In May 843, Breton leader
Nominoe took advantage of the confusion in the Frankish
Carolingian Empire to consolidate his territory. In alliance with a rebel Frank,
Lambert II of Nantes and the Norse warlord
Hastein, Nominoe's son
Erispoe defeated the Franks at the
Battle of Messac, killing
Count Renaud of
Nantes. In June 843 the Norse attacked and sacked the Frankish-controlled city of
Nantes as it was bereft of defenders due to the Battle of Messac. They sailed up the Loire river with a fleet of 67 ships. Crowds had gathered to celebrate the
feast of St. John. Most historians think that the raid was led by a Norse leader called Asgeir who was known for raiding up the River
Seine. It is also quite possible that among the Norse leaders at Nantes was Hastein. The Breton army under Nominoe in 845 defeated the forces of
Charles the Bald, King of
West Francia, at the
Battle of Ballon, in the eastern part of Brittany near
Redon and the Frankish border. Nominoe gained control over
Rennes and Nantes, which had previously formed part of a Frankish border zone known as the
Breton March. The Frankish army was again defeated in 851 at the
Battle of Jengland by the Bretons under Erispoe and control over Rennes, Nantes and the
Pays de Retz was secured. Consequently, the Franks recognised the independence of Brittany and determined borders between the two states. Under
Salomon, King of Brittany, Hastein's Norse in 865 united with the Bretons again to defeat a Frankish army at the
Battle of Brissarthe, near modern-day
Le Mans. Two Frankish leaders, Robert the Strong and
Ranulf I of Aquitaine, were killed. The Franks were forced to confirm Brittany's independence from the Franks and an expanded Breton territory. The Norse tactically helped their Breton allies by making devastating pillaging raids on the Frankish kingdom. In 867 Hastein's forces ravaged
Bourges and a year later attacked
Orléans. Peace lasted until the spring of 872 when the Norse fleet sailed up the
Maine and occupied
Angers, which led to a siege by Charles the Bald. A peace was agreed in October 873. ==Norse occupation==