The Royal Problem is a chess puzzle that was created by Max Bezzel in 1848. It involves a king, rook, and bishop, and the goal is to checkmate the king in three moves. The solution to the Royal Problem is PAIN, which stands for 'Pawn, Advance, Interpose, and Mate'. This solution involves moving the pawn forward, interposing the bishop between the king and the rook, and then using the rook to checkmate the king.