Morcar was the Earl of Northumbria from 1065-1066. He was the son of Ælfgar (earl of Mercia) and brother of Eadwine (or Edwin), earl of Mercia. He was the grandson of Leofric and Godiva. Morcar rose to power at the appointment of the thegns in York due to the tyrannical rule of Tostig, the brother of Harold Godiwnson and son of Earl Godwin of Wessex. Tostig was an incapable leader, and Harold banished him due to the surmounting pressure of the thegns, and he officially appointed Morcar as Earl of Northumbria.
According to the Anglo-Saxon Chronicle:
They then sent after Morkar, son of Earl Elgar, and chose him for their earl. He went south with all the shire, and with Nottinghamshire and Derbyshire and Lincolnshire, till he came to Northampton; where his brother Edwin came to meet him with the men that were in his earldom. Many Britons also came with him. Harold also there met them; on whom they imposed an errand to King Edward, sending also messengers with him, and requesting that they might have Morcar for their earl.
Tostig later returned with Harald Hardrada, King of Norway, to challenge Morcar and his brother Edwin. Tostig and Harald defeated the two brothers at Fulford on September 20, 1066.
And Morcar the earl, and Edwin the earl, fought against them; and the king of the Norwegians had the victory. And it was made known to King Harold how it there was done, and had happened; and he came there with a great army of English men, and met him at Stanfordbridge, and slew him and the earl Tosty, and boldly overcame all the army.
Harold Godwinson, then King Harold of England following Edward the Confessor’s death earlier in the year, raced north to protect his earls, defeating Tostig and Harald at the Battle of Stamford Bridge on September 28. After the battle, Harold immediately marched south to meet the invading forces of William of Normandy. Edwin and Morcar were both reluctant to join Harold, and instead went to London after the battle in most likely an attempt to seek the English throne for themselves. Eventually, they agreed to the Witan’s decision to elect Edgar the Etheling as king, though Edgar was never officially crowned as such. Duke William, instead, was crowned King of England, and both Edwin and Morcar submitted to his rule.
And the while, William the earl landed at Hastings, on St. Michael’s-day: and Harold came from the north, and fought against him before all his army had come up: and there he fell, and his two brothers, Girth and Leofwin; and William subdued this land.
From 1067-1068, Edwin and Morcar and Edgar the Etheling lived in Normandy as hostages of William. When they were finally allowed to return to the earldoms in England, they fomented rebellion against William. The Duke of Normandy eventually crushed their rebellion. Edwin’s own men betrayed and killed him. William captured Morcar, imprisoning him in Normandy for a second time.
In 1087, William released Morcar, who returned to England with William Rufus. Rufus imprisoned Morcar at Winchester, where he supposedly died.