The Wars of the Roses were a series of civil wars fought in medieval England from 1455 to 1487 between the House of Lancaster and the House of York. The name Wars of the Roses is based on the badges used by the two sides, the red rose for the Lancastrians and the white rose for the Yorkists. Major causes of the conflict include:
1) both houses were direct descendents of king Edward III;
2) the ruling Lancastrian king, Henry VI, surrounded himself with unpopular nobles;
3) the civil unrest of much of the population;
4) the availability of many powerful lords with their own private armies; and
5) the untimely episodes of mental illness by king Henry VI.

The Origins of the Wars of the Roses
It was in this year [1411], that Richard Plantagenet was born to Richard, fifth Earl of Cambridge and Anne Mortimer. His father was the son of Edmund, the first Duke of York, who was in turn the fourth son of Edward III. If Henry VI had died before 1453, the year of the birth of Edward, Prince of Wales, then Richard would have undoubtedly been crowned King of England, since there was no other noble (since the death of Henry VI's uncle and heir Humphrey, Duke of Gloucester, who had died in 1447) with such a strong claim to the throne at that time, other than Richard himself. Being so highly placed in the royal household, Richard was destined to play a significant role in the Government and politics of England throughout his lifetime and in England's affairs in France during the later stages of the Hundred Years War. He was appointed Lieutenant of France in 1436. Throughout his service in Europe, he had to pay for the services of his men and finance the army in France from his own personal funds.

Although York was a wealthy man in his own right, (York was the sole benefactor of the childless Edmund Mortimer, who had died of plague in Ireland in 1425). It was his marriage to Cicely Neville in 1438 (who was known as 'The Rose of Raby'), daughter to Ralph Neville, Earl of Westmoreland and sister of Richard Neville, Earl of Salisbury, which had brought him great wealth. Thus, he was able, albiet unhappily in doing so, to fund the English army overseas. By the time he left France, York had forwarded some Ł38,000 of his own money to maintain English interests in France. To add insult to injury, in 1445 he was replaced as Lieutenant of France by Edmund Beaufort, Duke of Somerset. It is not to be doubted that it was on Somerset's advice (who was Henry VI cousin, and someone Henry trusted more than the Duke of York) that Henry VI created York Lieutenant of Ireland, which was in reality, exile by office. Somerset was no doubt fearful of York, a fear enhanced by the fact that Somerset, a man whom York equally detested, and a favourite of Henry VI was forwarded funds to the sum of Ł25,000 to sustain the king's army in France.
Not only did York detest Somerset because of his favouritism with the king, but he also detested the fact that he had been given the office he had previously held in France and the funds to support it, despite his inability as a soldier. York's fears over the management of the campaign in France was soon realised, as the war began to go badly for the English. The Duke of Somerset was personally responsible for the surrender of the strategic town of Rouen which subsequently led to the fall of Normandy to Charles VII of France.