Earl Castle Stewart, in the County Tyrone, is a title in the Peerage of Ireland. It was created in 1800 for . The Earls Castle Stewart claim to be the head representatives in the pure male line of the Scottish Royal House of Stuart. They are directly descended from Sir Walter Stewart (died 1425), Keeper of Dumbarton Castle, younger son of Murdoch Stewart, 2nd Duke of Albany, son of Robert Stewart, 1st Duke of Albany, younger son of King Robert II of Scotland. One of Sir Walter's sons, Andrew Stuart, was created Lord Avandale (or Avondale) in 1459 and became Lord Chancellor of Scotland from 1460 to 1482. Another son, Walter Stewart, became feudal Baron of Morphie and was legitimised in 1479. His grandson Andrew Stewart was created Lord Avondale circa 1499, a revival of the title which had b