Count Michael George (Michal Jerzy) Mniszech (1748-1806) was Grand Marshal of the Crown of Poland, historian and economist. He married Ursula (Urszula) Zamoyska (1750-1808), niece of King Stanislas Augustus Poniatowski. They had a son, Charles, and a daughter, Isabella, who became Princess Radziwill.
In 1791, Count and Countess Mniszech stayed in Vienna where Fger painted the present miniatures and another pair of large miniatures of them, now in the Nationalmuseum, Warsaw. A slightly smaller version of the portrait of Countess Mniszech, from the Ostermann Collection, Darmstadt, is illustrated in G. Biermann, Deutsches Barock und Rokoko, Leipzig, 1914, II, p. 716, no. 1266.
For a copy after the present miniature depicting Countess Mniszech, by Wincenty Lesseur, dated 1794, see L. R. Schidlof, The Miniature in Europe, Graz, 1964, IV, pl. 359, no. 731. A full-length portrait of her, also by Lesseur, dated 1796, is illustrated in the exhibition catalogue Miniaturen von Wincenty Lesseur und Waleria Tarnowska, Rapperswil, Polenmuseum, 1994, no. 75. A miniature of Count Mniszech by Lesseur after Lampi was in the Brewster collection, sold Sotheby's, London, 14 December 1995, lot 69.