In Castling, the King must be moved first, or before the Rook is quitted. If the Rook be quitted before the King is touched, the opposing player may demand that the move of the Rook shall stand without the Castling being completed.
Howard StauntonEach player, it will be observed, has eight superior Pieces or officers, and eight minor ones which are called Pawns; and, for the purpose of distinction, the Pieces and Pawns of one party are of a different color from those of the other.
Howard Staunton