Malcolm was the eldest son of King Duncan I, who was killed in battle by Macbeth on August 15, 1040, when Malcolm was (probably) still a child. His family attempted to overthrow Macbeth in 1045, but all that did was get his grandfather killed. By this time, and for most of Macbeth’s 17-year reign, Malcolm was hidden away out of the country, possibly in England at the court of Edward the Confessor.
In 1054, Siward (a kinsman of Malcolm’s mother) joined the fight, and various chroniclers report Macbeth’s death at the hand of Malcolm on August 15, 1057. Macbeth was succeeded by his stepson, who was quickly crowned at Scone, but Malcolm did away with him as well the following April and became king himself. Since then, Macbeth’s gone down in legend as a usurping tyrant with a crazy wife. Malcolm is remembered as a pretty decent king who managed to make peace with William the Conqueror and won lots of battles before dying on the field during an ambush in November 1093, after 35 years on the throne.