Robert the Strong
Settled back in Brittany, Hastein allied himself with Salomon, King of Brittany against the Franks in 866, and as part of a Viking-Breton army he killed Robert the Strong at the Battle of Brissarthe near Châteauneuf-sur-Sarthe. In 867 he went on to ravage Bourges and a year later attacked Orléans. Peace lasted until spring 872 when the Viking fleet sailed up the Maine and occupied Angers, which led to a siege by the Frankish king Charles the Bald and a peace being agreed in October 873.