About Morcar, Earl of Northumbria
Morcar (or Morkere) (Old English: Mōrcǣr) (died after 1087) was the son of Ælfgār (earl of Mercia) and brother of Ēadwine. He was himself the earl of Northumbria from 1065 to 1066, when he was replaced by William the Conqueror with Copsi.
Peerage of England Preceded by Tostig Earl of Northumbria 1065–1066 Succeeded by Copsi
He was son of Ælfgar, earl of the Mercians, and was probably, along with his elder brother, Edwin or Eadwine, earl of the Mercians, concerned in stirring up the Northumbrians in 1065 to revolt against their earl, Tostig, the son of Earl Godwin.
He was chosen earl by the rebels at York in October. He at once satisfied the people of the Bernician district by making over the government of the country beyond the Tyne to Oswulf, the eldest son of Eadwulf, the Bernician earl, who had been slain by Siward in 1041. Marching southwards with the rebels, he was joined by the men of Nottingham, Derby, and Lincoln, members of the old Danish confederacy of towns, and met Edwin, Earl of Mercia, who was at the head of a force of Mercians and Welshmen, at Northampton. There the brothers and their rebel army considered proposals for peace offered to them by Earl Harold Godwinson. Negotiations were continued at Oxford, where, the Northumbrians insisting on the recognition of Morcar, Harold yielded on the 28th, and Morcar's election was legalised. 
On the death of Edward the Confessor, Morcar professedly supported Harold, but the people of his earldom were dissatisfied, and 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 III 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. 
York was surrendered, and Harold Godwinson had to march in haste to save the north by the battle of Stamford Bridge. Ungrateful for this deliverance, Morcar and his brother held back the forces of the north from joining Harold, in the defence of the kingdom against the Normans. After the battle of Hastings, Morcar and his brother arrived at London, sent their sister Aldgyth, Harold's widow, to Chester, and urged the citizens to raise one or other of them to the throne. 
They concurred in the election of Edgar the Ætheling, but disappointed of their hope left the city with their forces and returned to the north, believing that the Conqueror would not advance so far. Before long, however, they met William of Normandy either at Berkhamstead, or more probably at Barking, after his coronation. William accepted their submission, received from them gifts and hostages, and they were reinstated. The Conqueror carried Morcar and his brother with him into Normandy in 1067, and after his return kept them at his court. 
In 1068, they withdrew from the court, reached their earldoms, and rebelled against William. They were supported by a large number both of English and Welsh; the clergy, the monks, and the poor were strongly on their side, and messages were sent to every part of the kingdom to stir up resistance. Morcar's activity may perhaps be inferred from the prominent part taken in the movement by York. It seems probable, however, that Eadgar was nominally the head of the rebellion, and that he was specially upheld by the Bernician district under Gospatric. Morcar and his brother were not inclined to risk too much ; they advanced with their men to Warwick, and there made submission to the Conqueror, were pardoned, and again kept at court, the king treating them with an appearance of favour. On their defection, the rebellion came to nothing. In 1071, some mischief was made between them and the king, and William, it is said, was about to send them to prison, but they escaped secretly from the court. 
After wandering about for a while, keeping to wild country, they separated, and Morcar joined the insurgents in the Isle of Ely, and remained with them until the surrender of the island. Morcar, it is said, surrendered himself on the assurance that the king would pardon him and receive him as a loyal friend. William, however, committed him to the custody of Roger de Beaumont, who kept him closely imprisoned in Normandy. 
When the king was on his deathbed in 1087, he ordered that Morcar should be released, in common with others whom he had kept in prison in England and Normandy, on condition that they took an oath not to disturb the peace in either land. He was not long out of prison, for William Rufus took him to England with him, and on arriving at Winchester put him in prison there. Nothing further is known about him, and it is therefore probable that he died in prison.  Popular culture
Morcar has been portrayed by Noel Johnson in the two-part BBC TV play Conquest (1966), part of the series Theatre 625, and by Simon Rouse in the TV drama Blood Royal: William the Conqueror (1990). He is a significant character in Man With a Sword by Henry Treece, where him and Hereward the Wake are shown as becoming allies and friends in spite of some past clashes. He is mentioned in Alice's Adventures in Wonderland when the mouse attempts to dry itself and other characters by reciting a dry example of English history. References
This article incorporates text from a publication now in the public domain: Hunt, William (1894). "Morcar". In Lee, Sidney. Dictionary of National Biography 38. London: Smith, Elder & Co.