Related Clues:

• Class system probed by Left's Social Services secretary
• Rook; stronghold
• Keep a piece
• Keep a piece in the corner
• Shed left on English fortification
• A rook on board
• Make chess move involving king and rook
• Stronghold, rook
• Man, learner in class
• Rook I released from Eleanor's place in Spain
• Man I ejected from Isabella's place
• Decent in two ways
• Rook (chess)
• Rook, on chess board
• House of Windsor?