Stewart of Darnley Stewart of Darnley Stewart of Darnley was a notable Scots family, a branch of the Clan Stewart, who provided the English Stuart monarchs with their male-line Stuart descent, after the reunion of their branch with the royal Scottish branch, which led to the ultimate union of the two main kingdoms of Great Britain: England and Scotland. In 1565 the House of Stewart of Darnley was re-united with the Royal House of Stewart when Henry Stuart, Lord Darnley married his first cousin, Mary, Queen of Scots, both being grandchildren of Margaret Tudor, daughter of King Henry VII of England, and hence
James VI and I Stuart, Lord Darnley. Both Mary and Darnley were great-grandchildren of Henry VII of England through Margaret Tudor, the older sister of Henry VIII. Mary's rule over Scotland was insecure, and she and her husband, being Roman Catholics, faced a rebellion by Protestant noblemen. During Mary's and Darnley's difficult marriage, Darnley secretly allied himself with the rebels and conspired in the murder of the Queen's private secretary, David Rizzio, just three months before James's birth. James was born on 19 June 1566 at Edinburgh Castle, and as the eldest son and heir apparent of the monarch automatically became Duke of Rothesay