Malcolm’s death is soon followed by that of his queen, Margaret of Wessex, just days after receiving the news of her husband's death in battle.
The death of Malcolm and his heir means that there is a dispute over the succession between Malcolm’s surviving sons and his younger brother Donald Bane.
Donald's activities during the reign of his elder brother Malcolm III (Máel Coluim mac Donnchada) are not recorded.
It appears that he was not his brother's chosen heir, contrary to earlier custom, but that Malcolm had designated Edward, his eldest son by Margaret of Wessex, as the king to come If this was Malcolm's intent, his death and that of Edward have confounded his plans.
John of Fordun reports that Donald invaded the kingdom after Margaret's death "at the head of a numerous band", and laid siege to Edinburgh with Malcolm's sons by Margaret inside.
Fordun has Edgar Ætheling, concerned for his nephews' well-being, take the sons of Malcolm and Margaret—Edmund and his younger brothers Edgar, Alexander and David—to England.
Andrew of Wyntoun's much simpler account has Donald become king and banish his nephews.
The Anglo-Saxon Chronicle records only that Donald was chosen as king and expelled the English from the court.
The event allows Duncan, the eldest son of Malcolm and his first wife Ingibiorg Finnsdottir, given over as a hostage by his father in 1072, to lay claim to the throne.
In his attempt to depose his uncle, he has the support of William II, in exchange of an oath of fealty to his patron.
Duncan’s father, who had many sons, appears to have made no effort to obtain Duncan's return.
He had been raised in the Anglo-Norman court of William I, becoming familiar with the culture, education, and institutions of his hosts.
Trained as a Norman knight, he had participating in the campaigns of William I.
According to Florence of Worcester, in 1087, when William I died, and his eldest surviving son Robert Curthose succeeded him as Duke of Normandy, Robert released Duncan from custody and had him officially knighted.
Allowed to leave the Duchy of Normandy, Duncan chose to join the court of Robert’s younger brother William Rufus.
Edward, the eldest paternal, half-brother of Duncan had been designated heir in his absence.
Duncan had notably chosen to stay with his adoptive culture, partly due to the influence of fifteen years of Norman life, partly in pursuit of personal wealth and glory.
Donald III has been unable to gain the support of certain landowners and church officials of the Scottish Lowlands, who had ties to the regime of his predecessor.
Duncan takes advantage, negotiating alliances with these disgruntled supporters of his fathers.
Gaining essential military and financial support for his cause.
While William II himself has no intention to join in the campaign, he lends Duncan part of the Norman army.
Duncan is able to recruit further levies from local barons and towns of England, and buys support with promises of land and privilege, estates and title.
