A catalogue of those highly celebrated and matchless chef d'œuvres of the Italian and English schools, viz. the Madonna del Sacco by Andrea del Sarto; and the Niobe, by the immortal Wilson: the former well known by the engravings of Morghen, and Bartolozzi, and the latter, of the incomparable Woollett. With a few other pictures by different masters; among which is, a landscape and figures by Ruysdael, in his best style; the genuine property of his late Royal Highness the Duke of Gloucester, deceased; and removed from his mansion in Upper Grosvenor Street. Which will be sold by auction by Mr. Christie, at his Great Room, Pall Mall, on Saturday, the 27th of May, 1806, at twelve o'clock.