[4] Edgar was brought up by the Confessor's wife, Edith, and he is recorded in the New Minster Liber Vitae as clito, the Latin for ætheling, a royal prince eligible for the throne.

However, the avaricious ambitions that had been aroused across north-western Europe by the Confessor's lack of an heir prior to 1057, and by the king's failure thereafter to prepare the way for Edgar to succeed him, removed any prospect of a peaceful hereditary succession.

[2] Following Harold's death at the Battle of Hastings against the invading Normans in October 1066, some of the Anglo-Saxon leaders decided to back young Edgar's claim to the throne.

In early December, the remaining members of the Witan in London met and resolved to take the young uncrowned king out to meet William to submit to him at Berkhamsted, quietly setting aside Edgar's election.

Edgar might have been involved in the abortive rebellion of the Earls Edwin and Morcar in 1068, or he might have been attempting to return to Hungary with his family and been blown off course; in any case, in that year he arrived with his mother and sisters at the court of King Malcolm III of Scotland.

[10] When the rebellion that resulted in the Harrying of the North broke out in Northumbria at the beginning of 1069, Edgar returned to England with other rebels who had fled to Scotland, to become the leader, or at least the figurehead, of the revolt.

Their combined forces overwhelmed the Normans at York and took control of Northumbria, but a small seaborne raid which Edgar led into the former Kingdom of Lindsey ended in disaster, and he escaped with only a handful of followers to rejoin the main army.

Shortly after his arrival there, he received an offer from Philip I, King of France, who was also at odds with William, of a castle and lands near the borders of Normandy from where he would be able to raid his enemies' homeland.

These were presumably former possessions of William and his supporters in Normandy, confiscated by Robert and distributed to his own followers, including Edgar, but restored to their previous owners by the terms of the peace agreement.

[19] Having returned to England, Edgar went to Scotland again in 1093, on a diplomatic mission for William to negotiate with Malcolm, who was dissatisfied with the Norman failure to implement in full the terms of the 1091 treaty.

This dispute led to war, and within the year Malcolm had invaded England and had been killed along with his designated heir Edward, eldest of his sons by Margaret, in the Battle of Alnwick.

[20][non-primary source needed] Another effort to restore the Anglo-Norman interest through sponsorship of Malcolm's sons was launched in 1097, and Edgar made yet another journey to Scotland, this time in command of an invading army.

[21][2] According to Orderic, Edgar was the commander of an English fleet which operated off the coast of the region of Syria in support of the First Crusade, whose crews eventually burned their dilapidated ships and joined the advance by land to Jerusalem.

[22][non-primary source needed] This is doubtful, for this fleet is known to have arrived off the Syrian coast by March 1098; since Edgar invaded Scotland late in 1097, he could not have made the voyage in the time available.

Some modern historians have suggested that at some point during these years Edgar served in the Varangian Guard of the Byzantine Empire, a unit which was at that time composed primarily of English emigrants, but this is unsupported by evidence.

William of Malmesbury stated that on his way back from Jerusalem, Edgar was given rich gifts by both the Byzantine and the German emperors, each of whom offered him an honoured place at court, but that he insisted on returning home instead.