Alexander I lived from 1077 to 23 April 1124 and was King of Scotland from 8 January 1107 to 23 April 1124. The wider picture in Scotland at the time is set out in our Historical Timeline.
When Edgar died he bequeathed only the northern half of his Kingdom to Alexander. The lands south of the Forth and Clyde were made into a separate earldom and placed in the care of another brother, David, who went on to become David I.
Alexander gained a reputation for fierceness after suppressing a revolt by descendents of King Lulach in Moray. On the other hand he was also know for his support of the church and his piety, which included the foundation of abbeys on Inchcolm and at Scone.
Alexander continued his predecessor's close (and subservient) links with Henry I of England, in 1114 commanding part of Henry's army on campaign in Wales. He also married Henry's illegitimate daughter Sybilla (Henry had married Alexander's sister Matilda). Sybilla died suddenly in July 1122, leaving no children. Alexander died at Stirling on 23 April 1124. He was succeeded by his brother, David I.