We all know of the War of the Roses ,the conflict which arose between the two main branches of the royal family of England : House Lancaster and House York (respectively the descendants of the Duke of York, Edmund of Langley and the Duke of Lancaster,John of Gaunt) but why did it actually take place ?
The difficulty originated among the children and descendants of King Edward III, Edward ‘s sons who were very warlike young men,the most remarkable of these warlike princes were Edward the Black Prince(who was the eldest son)and John of Gaunt(the 3rd in line).The Black Prince did not live to succeed his father and inherit the throne but his son and his heir Richard succeeded to the throne as King Richard II(as he was the oldest living son of the oldest son, his claim could not be disputed).
However,Richard had a cousin named Henry Boiling(later known as Henry IV), a young man of just about his own age ,he was the son of his uncle John. Henry, who was driven at last, by a peculiar train of circumstances, to rise against Richard which resulted in his depostion, and Henry obtaining possession of the kingdom. It was thus that the house of Lancaster first became established on the throne.
Therefore,the contest and the dispute arose from the fact that Richard II should not have been succeeded by the Lancastrian Henry IV but by Edmund Mortimer(descendant of the Duke of Clarence 2nd in line) which led later the Yorkist Richard,Earl of Cambridge,who married Mortimer’s sister Anne to conspire against Henry V to seat the childless Mortimer on the throne and thereafter have his own descendants succeed(the most notable ones were Edward IV and Richard III who did in fact succeed later to the crown but that’s another story to tell.)