As head of the powerful family of
Stewart of Darnley he was created Governor of
Rothesay Castle in 1465 and appointed
Warden of the
West Marches of Scotland. When the male line of the Earldom of Lennox became extinct he was heir to half of the lands and made a deal with the co-heir in which he was made
Earl of Lennox in 1473. The succession was disputed by John of Haldane, who claimed succession through descent from
Duncan, 8th earl. Darnley, however, prevailed and his right to the earldom was not disputed for the last seven years of his life. He was a loyal ally of
James III during his war against the rebel lords led by
Archibald Douglas, 5th Earl of Angus. After the death of the King at the
Battle of Sauchieburn and the coronation of his underage son
James IV he raised an army to fight against the rebel lords who now controlled the government. The rebels had seized control of
Edinburgh Castle and now had possession of the important royal
artillery. Included in the arsenal of Edinburgh Castle was the cannon
Mons Meg which had been a wedding gift from
Philip the Good, Duke of Burgundy to the
King of Scots a generation earlier. Using this weapon they laid siege to
Crookston Castle, seat of the Stewarts of
Darnley, forcing the Earl of Lennox to surrender. After his surrender he was allowed to keep his lands and they passed to his eldest son
Matthew Stewart, 2nd Earl of Lennox who was one of the leaders of the Scottish army killed at the
Battle of Flodden. ==Marriage==