Richard III was Edward IV's youngest brother. He was widely believed to be deformed, but whatever the deformity, Richard went onto become a skilled ruler and military commander. During the reign of Edward IV, Richard was appointed the Governor of th North, and later, the Lord High Admiral of England.
After Edward's death, Richard was made Lord Protector of Edward's sons. Desiring to be King, Richard claimed that the boys were illegitimate, used his power to have Parliament name them as such, and proclaimed himself King. Richard then had the boys imprisoned in the Tower and was likely responsible for ordering their deaths.
The Princes in the Tower