With the Act of Accord naming the Yorkists as next in line for the throne, Henry’s own son, Edward, Prince of Wales, was disinherited. Queen Margaret and the Lancastrians now had a powerful motive for continuing the civil war. Many saw the Act as a violation of the rights of inheritance, and in a society based on landed wealth this was a serious issue indeed. The Act also changed the course of the Wars. The battle was no longer for supremacy of individual factions - it was for the throne itself.

At York, Margaret publicly protested against the Act of Accord and challenged York to settle the issue in battle. All those nobles who had not agreed with the Act joined her, and in late November this army started marching southwards. York, still in the south, began a propaganda campaign directed at instilling the southerners with fear of Margaret’s northern hordes. In early December, York and the Earl of Salisbury marched out of London with about 5,000 men, leaving the Earl of Warwick to maintain control of the capital. York headed for his castle at Sandal, two miles west of Wakefield, recruiting on the way. When he arrived, he set his men to building trenches and positioning guns around the castle. It seemed they were in a good defensive position if the Lancastrians attacked. His son, the Earl of March, was recruiting in Wales, and York intended to await his arrival with reinforcements.

During the Christmas season, Somerset met with York and it was agreed that a truce would prevail until after the feast of Epiphany on January 6. The Lancastrians, however, did not intend to keep the truce and they moved part of their army closer to Sandal. On December 30 it is believed that a foraging party, sent out for supplies and information, was attacked by men under the command of Somerset and the Earl of Devon when returning to the castle. York could see the skirmish from the castle, and could also see a second army closing in behind. Believing this to be a relieving force under the command of Lord John Neville (who had unbeknownst to York, changed sides), York decided to take advantage of what he thought was a rear attack on Somerset. As soon as he reached the fighting, York realized his mistake, but, believing that the men before him constituted the entire Lancastrian army, decided to give battle.

It was now that the other Lancastrian forces encamped around Sandal began mobilizing and advancing on the battle area. With the arrival of the last the Lancastrians, Lord Clifford's men, the Yorkists were totally surrounded. After York himself was pulled from his horse and killed, all Yorkist resistance broke down. The Earl of Wiltshire and his men took possession of Sandal.

York's son, Edmund, was captured by Lord Clifford at Wakefield Bridge. Clifford is supposed to have said, "By God's blood, thy father slew mine, and so will I do thee and all thy kin," and drew his sword and killed him. Salisbury was captured, taken to Pontefract, and beheaded the next day. He was condemned by Henry Percy, Earl of Northumberland, Henry Beaufort, Duke of Somerset, and John Clifford, all who had had fathers killed at St. Albans. His head, along with York’s and Rutland’s, were placed on spikes and exhibited above the Micklegate Bar in York; apparently a paper crown was placed on York’s head. The hatred between the two sides was now intense and the violence displayed at Wakefield set a precedent for the rest of the Wars.

The death of their fathers left the Earl of March, now nominally the Duke of York, and the Earl of Warwick two of the richest magnates in England. However Henry VI refused to acknowledge March’s right to succeed his father and did not allow him to bear the title Earl of Chester, as he was entitled to do as heir to the throne under the Act of Accord.

After the Yorkists�?devastating defeat the way to London lay open for the Lancastrians. Margaret was marching south at the head of an army provided by Scotland. In return for these troops, Margaret agreed to cede the town of Berwick to the Scots, and to marry Prince Edward to the Scots Princess Margaret. The main Lancastrian army was encamped near York and the two forces planned to meet up and march to London. Jasper Tudor, Earl of Pembroke, and James Butler, Earl of Wiltshire, had raised an army composed mainly of Welshmen, but also including French and Irish mercenaries. They were now marching east from Wales, hoping to link up with the main Lancastrian army.

The Yorkists again turned to propaganda, spreading news among the southerners that Margaret’s northern army had been given free reign to rape, rob and murder. This worked effectively, and the Yorkists were able to recruit large numbers of men who were eager to defend their homes against these savages. The Earl of March, at the head of an army, was hoping to link up with Warwick and intercept the Queen before she reached London. After hearing about Pembroke’s forces, however, he decided to turn his army west and deal with this threat first.

On the morning of February 2, March’s forces met with Pembroke’s at Mortimer’s Cross. On that morning both sides witnessed a natural phenomenon called a parhelion, when it appears that there are three suns in the sky. March quickly turned this to his advantage, claiming this was an omen from God, signifying the Trinity. He also read it as an indication of the reunion of the three sons (suns) of York, Edward, George and Richard. This boosted the morale of Edward’s soldiers. Edward later used “the sun in splendour�?as his personal livery badge.

The Yorkist army was about eleven thousand strong. The right flank was commanded by Walter Devereux, the center by March, and the left flank by Sir William Herbert. The Lancastrians were about eight thousand strong: the left flank, which included the more experienced and professional mercenaries, was under the command of Wiltshire, the centre under Pembroke, and the right flank under the joint command of Owen Tudor and Sir John Throckmorton. Wiltshire began hostilities by advancing on the York right wing, which was pushed back and scattered. Pembroke advanced on the Yorkist center, commanded by March, and both sides fought for some time, before the Yorkists began to gain ground and the Lancastrians broke and scattered westward. Owen Tudor attempted to encircle the Yorkists, but in doing so exposed his left flank to Herbert's forces. Herbert ordered his men to advance towards Tudor's forces, who could offer little resistance. Tudor tried to rally his troops, but they broke and scattered. It was clear that despite losing their right wing early on, the Yorkists looked set for victory. The Yorkist archers now began shooting volleys of arrows into the Lancastrian cavalry, causing their center to collapse. Realising the day was lost, Pembroke fled the field, leaving his men and his father behind. Wiltshire also later managed to escape.

About 4,000 men were killed in the battle, mostly Pembroke’s. March’s losses were light. The Yorkists pursued the fleeing Lancastrians all the way to Hereford, where, after a brief skirmish Owen Tudor and the remaining Lancastrian captains were captured. The next day, Tudor and Throckmorton were executed in the Hereford market place. This was the first in a line of victories for young Edward, and showed the Lancastrians that the new head of the house of York was a man to be feared.