The youngest of the sons of Malcolm Canmore, he was sent in 1093 to England along with his sister Matilda (who in 1100 married Henry I of England) and remained for several years at the English court. In 1107, when his elder brother Alexander succeeded to the throne, David became Prince of Cumbria with a territory which, besides part of Cumberland, included all Southern Scotland except the Lothians. By his marriage in 1113 to Matilda, widow of the Norman Earl of Northampton and daughter of the Saxon Earl of Northumbria, he became Earl of Huntingdon.
In 1124 he succeeded his brother on the Scottish throne; in 1127 he swore, with the other great barons of England, to maintain the right of his niece Matilda to the English crown. In 1135, he took up arms on her behalf when Stephen seized the throne and penetrated into England as far as Durham, where peace was purchased by the confirmation of the earldom of Huntingdon to his son Henry and the promise of that of Northumberland. In 1138 the war was renewed and David, deserted by Bruce and others of his Anglo-Norman vassals who owned large estates in England, was signally defeated at the "Battle of the Standards" near Northallerton.
The next year a second peace was concluded when the promised earldom of Northumberland was bestowed on Prince Henry. The rest of David's reign---which marks the end of Celtic and the beginning of Feudal Scotland---was devoted to the welding of the different races of Scotland into one nation, the civilization of the people by the erection of burghs, the promotion of trade, manufacturing and commerce, and the founding or restoration of bishoprics and religious houses.
According to Bellenden, "the crown was left indigent through ampliation of great rents to the church", a state of matters that led James I to remark, while standing by David's tomb at Dunfermline, that "he was ane sair sanct for the crown". He is often called St.David though he was never formally canonized but his name was inserted in the calendar prefixed to Laud's Prayer Book for Scotland (1637). He died at Carlisle and was succeeded by his grandson, Malcolm.
Source: Leo van de Pas