When David's brother Alexander I died in 1124, David chose, with the backing of Henry I, to take the Kingdom of Scotland (Alba) for himself. He was forced to engage in warfare against his rival and nephew, Máel Coluim mac Alaxandair. Subduing the latter seems to have taken David ten years, a struggle that involved the destruction of Óengus, Mormaer of Moray. David's victory allowed expansion of control over more distant regions theoretically part of his Kingdom. After the death of his former patron Henry I, David supported the claims of Henry's daughter and his own niece, Empress Matilda, to the throne of England. In the process, he came into conflict with King Stephen and was able to expand his power in northern England, despite his defeat at the Battle of the Standard in 1138.
The term "Davidian Revolution" is used by many scholars to summarise the changes which took place in Scotland during his reign. These included his foundation of burghs and regional markets, implementation of the ideals of Gregorian Reform, foundation of monasteries, Normanisation of the Scottish government, and the introduction of feudalism through immigrant French and Anglo-French knights.
The early years of David I are the most obscure of his life. As there is little documented evidence, historians can only guess at most of David's activities in this period.
David was born on a date unknown in 1084 in Scotland. He was probably the eighth son of King Malcolm III, and certainly the sixth and youngest born by Malcolm's second wife, Margaret of Wessex. He was the grandson of the ill-fated King Duncan I.
In 1093 King Máel Coluim and David's brother Edward were killed at the River Aln during an invasion of Northumberland. David and his two brothers Alexander and Edgar, both future kings of Scotland, were probably present when their mother died shortly afterwards. According to later medieval tradition, the three brothers were in Edinburgh when they were besieged by their paternal uncle Donald.