The younger son of Edmund I, king of the English, Edgar was made king of the Mercians and Northumbrians in place of Eadwig, his brother, who was deposed. On Eadwig's death (Oct. 1, 959), Edgar succeeded to the West Saxon throne. His ecclesiastical policy was also that of St. Dunstan (Dunstan of Canterbury, Saint), whom Edgar recalled from exile and made archbishop of Canterbury; Dunstan insisted on strict observance of the Benedictine Rule. The king supported Archbishop Oswald of York and Bishop Aethelwold of Winchester in founding abbeys and reforming the church. Edgar's laws were important; they were the first in England to prescribe penalties for nonpayment of tithes and Peter's pence, the annual contribution made by Roman Catholics for support of the Holy See. He legislated also for the Danelaw, which still enjoyed a certain autonomy, and reformed the coinage, ensuring that no town or village was farther than 30 miles (50 km) from a royal mint.

king of Scots from 1097, eldest surviving son of Malcolm III Canmore and Queen Margaret (granddaughter of King Edmund II of England) and thus the first king of the Scots to unite Celtic and Anglo-Saxon blood.

As vassal to King William II Rufus of England, he was placed on the Scottish throne to succeed the Celtic, anti-English Donald Bane, his uncle, who was deposed. In 1098 Edgar ceded the Hebrides to Magnus III, king of Norway, who had been raiding the islands. Edgar was a generous benefactor of the church; a contemporary historian (St. Aelred of Rievaulx) called him the equal of Edward the Confessor in personal merit. He died unmarried and was succeeded by his brother Alexander I.