He was Duke of Albany, Regent, 1406-1420 (letter from Philip B. Stewart, 6 Sabal Ct., Sewal's Pt., Stuart Fl., 4/24/1990).
The third son of Robert II. Hostage in England, 1360. Baron of Menteith on marriage, 1361. Earl of Fife and Menteith, 1371. Hereditary governor of Stirling, 1373. Placed in line of succession. Chamberlain of Scotland, 1382-1407. Took part in raids into Northumberland and Cumberland, 1385-1386. Led invasion of 1388. Provisional guardian of Scotland, 1388-1399. Created Duke of Albany, 1398. member of Rothesay's council, 1399. Reinstated as governor after Rothesay's arrest and death, 1402. His forces defeated by English, 1402. Supposed to have acted with Hotspur, 1403. Regent of Scotland on capture of Prince James and death of Robert III, 1406. His supposed connivance at imprisonment of James I in England not substantiated. Crushed rebellion of Donald Macdonald, second lord of the Isles, who claimed Albany's earldom of Ross, 1411. Caused erection of Inverness Castle. Demanded release of James I, 1416. Protected Thomas Warde, the pretended Richard II of England. Made "foul raid" against Roxburgh, 1417. Granted charter, 1420. Buried at Dunfermline (The concise dictionary of national biography. Part 1 : from the beginnings till 1900. London : Oxford University Press, 1969, pg. 1250).
He actually was in charge since his brother Robert III was unable to exert rule due to injuries from his riding accident (Williamson, David. Debrett's kings and queens of Britain. Topsfield, Mass. : Salem House Publishers, 1986, pg. 229. The concise dictionary..., pg. 1112)
Regent of Scotland, 1406-1420. Baron of Menteith, 1st Duke of Albany.