Robert III was born c.1336, the son of the later Robert II and his first wife Elizabeth Mure. Christianed John he assumed the name Robert on becoming king, considering John as unlucky following the tribulations of King John Balliol.
On reaching thirty Robert married David II's niece, Annabella Drummond; a political move indicating David II regarded him as a suitable heir and not his father. Had David II survived Robert's father he may have got his wish, instead the father became Robert II on David II's death in 1371.
Robert was now to become the King's Lieutenant in 1384, taking effective control of the south of Scotland. His brothers also jostled for control of their father's kingdom and took advantage when the new Lieutenant was lamed by a kick from a horse.
Still, Robert assumed the kingdom on the death of his father in 1390. As Robert III he struggled to exert control over the north of Scotland. He continued his late father's policy by giving honours to his relations:- his brother Robert the Earl of Fife was made Duke of Albany; his eldest son and heir Prince David, the Earl of Carrick was made Duke of Rothesay. (Rothesay was later made a Royal burgh in 1400.) Both men led campaigns to maintain control in the north.
Troubles also began to brew in the south. On the death of John Dennistoun, the keeper of Dumbarton Castle, his brother Walter took the castle. Even withstanding a seige in 1398 by Robert III, Walter remained secure. A one-time parson, Walter Dennistoun demanded that he be given the post of Bishop of St. Andrews. Eventually in 1402 the Duke of Albany agreed but before Walter assumed his role he was to die.
As heir the Duke of Rothesay was gaining power. Robert III halted his rise by blocking David's proposed marriage to the Earl of March's daughter. This would have gave the Duke influence in setting Scotland's foreign policy towards England. David took revenge by asserting the role of King's Lieutenant in 1399. The son had now followed the father.
David then courted the Earl of Douglas's daughter. Douglas was a rival of the Earl of March who now in desperation turned to the English king Henry IV for help. Henry IV brought an army to Edinburgh but achieved little.
By now the Duke of Albany determined to ruin his nephew's rise. He circulated tales that Prince David was power mad and in abuse of his office. After Queen Annabella's death in 1401, Albany convinced Robert III to arrest his heir. Confined in Albany's Falkland Castle, Prince David starved to death in the dungeon in March 1402. Albany assumed the role of King's Lieutenant.
Albany's main ally, the 4th Earl of Douglas, now initiated a battle with England. The Battle of Homildon Hill in 1402 was a disaster for the Scots and a well-timed facesaver for Henry IV struggling against the Welsh. Douglas was captured by the Northumbrian Percys and a relative of Drumry's Robert Livingston, Sir John of Callander was killed.
The capture of Douglas meant that Robert III could promote his remaining son James, the new Earl of Carrick, as heir. In 1406 both the Earl of Orkney Henry Sinclair and Sir David Fleming, a relative of the Garscadden Flemings, tried to assert royal power by using James against Albany and the Douglases. The plot failed; Fleming was killed and both Sinclair and Prince James fled en route to France.
On hearing that James was captured by English pirates and given to Henry IV, the aged Robert III was heartbroken. He died in the same year and buried in Paisley Abbey.