On the death of Edward the Confessor, Morcar professedly supported Harold, but the people of his earldom were dissatisfied. Harold visited York, the seat of Morcar's government, in the spring of 1066, and overcame their disaffection by peaceful means. In the summer, Morcar joined his brother Edwin in repulsing Tostig, who was ravaging the Mercian coast. When, however, Tostig and his ally Harald Hardrada invaded Northumbria in September, Morcar evidently was not ready to meet them; and it was not until York was threatened that, having then been joined by Edwin, he went out against them with a large army. The two earls were defeated at Fulford Gate, near York, in a fierce battle, in which, according to a Norse authority, Morcar seems to have been prominent.