The Old Royal House referred to in the crossword solution is the Tudor dynasty, which ruled England from 1485 to 1603. The Tudors were a Welsh-English family that rose to power during the Wars of the Roses and established the first monarchical dynasty of England since the Norman Conquest. They are best known for their strong religious policies, including the establishment of the Church of England, and for their influential monarchs, such as Henry VIII and Elizabeth I.