Henry Stuart, Lord Darnley not together in early 1545 and a letter of March 1566, from Mary Queen of Scots, indicates Darnley was then nineteen years old. Therefore the date 1546 would seem probable. A descendant of both James II of Scotland and Henry VII of England, Henry Stuart, Lord Darnley, was heir to two royal houses, the House of Stuart and the House of Tudor, thus he had claim to both the Scottish and English thrones, a claim that may have cost him his life. In 1545, his father, Matthew Stewart, 4th Earl of Lennox was found guilty of treason in Scotland for
Henry Stuart, Lord Darnley refused to accompany Mary to the nuptial Mass after the wedding itself. Soon after Mary married Darnley, she became aware of his vain, arrogant and unreliable qualities, which threatened the well-being of the state. Darnley was unpopular with the other nobles and had a violent streak, aggravated by his drinking. Mary refused to grant Darnley the Crown Matrimonial, which would have made him the successor to the throne if she died childless. By August 1565, less than a month after the marriage, William Cecil heard that Darnley's insolence had driven Lennox from the Scottish court. Mary soon became pregnant. Mary's