James VI of Scotland (who later became James I of England and Ireland) became king as a baby.
James Stuart, the son of Mary, Queen of Scots, and Henry Stuart, Lord Darnley, ascended to the Scottish throne in 1567 as an infant, following his mother's abdication. He was only about a year old at the time. Later, upon the death of Queen Elizabeth I in 1603, he also became King of England and Ireland, uniting the crowns. He ruled until his death in 1625.
