From the longer Wikipedia page 
The Princes in the Tower were Edward V of England and Richard of Shrewsbury, Duke of York. The two brothers were the only sons of Edward IV of England and Elizabeth Woodville alive at the time of their father's death. Then 12 and 9 years old, they were lodged in the Tower of London by the man appointed to look after them, their uncle, the Lord Protector: Richard, Duke of Gloucester. This was supposed to be in preparation for Edward's coronation as king. However, Richard took the throne for himself and the boys disappeared.
It is unclear what happened to the boys after they disappeared in the tower. It is generally assumed that they were murdered; there are several suspects who had motives for such an action. The murder may have occurred some time around 1483, but apart from their disappearance, the only evidence is circumstantial. Some believe that one, or both, princes were not murdered; some believe that one or both managed to escape. In 1487, Lambert Simnel initially claimed to be Richard, Duke of York, but later claimed to be Edward Plantagenet, 17th Earl of Warwick. From 1490 until his capture in 1497 Perkin Warbeck claimed to be Richard, Duke of York, who had supposedly escaped to Flanders. Warbeck's claim was supported by some contemporaries (including the aunt of the princes, Margaret of York).
In 1674 workmen at the Tower dug up a wooden box containing two small human skeletons. The bones were found in the ground near the White Tower, which is close to one reported site of their burial. The bones were widely accepted at the time as those of the princes, but this is not proven. King Charles II had the bones buried within Westminster Abbey.