1. Unresolved drama from the Hundred Years’ War. The English suffered a massive defeat at the end of the Hundred Years’ War, losing most of their land possessions in France, including Maine, Normandy and Bordeaux, and leaving many landowners impoverished and mercenaries who had picked up the habit of pillaging, plundering and violently taking whatever they wanted during the war.
2. Recent financial disaster. After the most recent outbreak of the Black Plague, the labor force had been devastated, driving up prices and the cost of labor and bringing widespread famine. At the same time, there was an entire population of new landholders on the rise becoming increasingly powerful and wealthy feudal lords, while older lords were in debt. Plus, war was expensive and the treasury was broke.
3. The peers got bored. While it sounds a little silly, it is not hard to imagine that England probably didn’t know what to do with itself at first when the Hundred Years’ War was over. Under the corrupted “livery and maintenance system,” or what was known as “bastard feudalism,” the peers could still quickly raise large, personal armies. Now all they needed was someone new to fight.
4. Henry VI was not a popular king. Both nobles and Parliament, including Richard of York, Richard III’s father, had major grudges against Henry’s favorites, Somerset and Suffolk, especially when they didn’t do these nobles any favors. Henry VI alienated most of the peerage while also upsetting the Commons at Parliament, and was frequently dealing with rebellions from the countryside (although so were later rulers). Not only did the birth of Henry’s heir complicate the question of succession and who would take power, but he also became mad, which allowed York to take power until he came to his senses again, beginning the long struggle for the crown between Lancaster and York.
5. Richard III. Richard is more or less responsible for the final stage of the Wars of the Roses, although it has also been argued that Edward IV’s highly concentrated power base made his brother’s usurpation possible.
Jokinen, Anniina. "Causes of the Wars of the Roses: An Overview." Luminarium Encyclopedia. Web. 26 Apr 2007. [2-16-2010]. <http://www.luminarium.org/encyclopedia/roseswarcauses.htm>
Wagner, John A. Encyclopedia of the Wars of the Roses. CA: ABC-CLIO, Inc. 2001.