Physical Dimensions: overall: 96.8 x 66 cm (38 1/8 x 26 in.)
Provenance: Possibly Harman van Swol; possibly (his sale, Jan Pietersz. Zomer, Amsterdam, 20 April 1707, no. 15). Acquired 1765 in Rotterdam by (Philippus Florentinus Vergeloo, Antwerp) for Count Johan Carl Philipp Cobenzl [1712-1770]; sold 1768 to Catherine II, empress of Russia [1729-1796], Saint Petersburg; Imperial Hermitage Gallery, Saint Petersburg; sold February 1931 through (Matthiesen Gallery, Berlin; P. & D. Colnaghi & Co., London; and M. Knoedler & Co., New York) to Andrew W. Mellon, Pittsburgh and Washington; deeded 30 March 1932 to The A. W. Mellon Educational and Charitable Trust, Pittsburgh; gift 1937 to NGA.
 In the 1707 sale in Amsterdam, a painting described as "Een Ambassadeur van Moscovien, van Rembrandt kragtig geschildert" (An Ambassador of Moscow, powerfully depicted by Rembrandt) may have been this work; the association of this painting with _A Polish Nobleman_ was first made in Stichting Foundation Rembrandt Research Project, _A Corpus of Rembrandt Paintings_, vol. 3, _1635–1642_, ed. Josua Bruyn et al., Dordrecht, Boston, and London, 1989: 247.
 On the identification of Cobenzl as the collector who sold the painting to Catherine II, and of Vergeloo as his source, see Catherine Phillips, "The Provenance of Rembrandt's 'Polish Nobleman' (1637) in the National Gallery of Art, Washington," _The Burlington Magazine_ 151 (February 2009): 84-85. When _A Polish Nobleman_ was first described in the catalogue of Catherine II's collection, compiled between 1773 and 1785, it bore the title "Portrait d'un Turc."