A Marble Portrait Head of a Man, Roman Imperial, circa 2nd Century A.D., on a 17th Century draped bust engraved in Greek for Poseidonios

with short incised beard, pronounced aquiline nose, deep-set eyes with engraved irises and drilled pupils, lined forehead, and receding hairline; the back of the head restored in marble.

Thomas Herbert, 8th Earl of Pembroke, 1656-1733, Wilton House, Wiltshire
Henry, 9th Earl of Pembroke, 1693-1749
Henry, 10th Earl of Pembroke, 1734-1794
George Augustus, 11th Earl of Pembroke, 1759-1827
Robert Henry, 12th Earl of Pembroke, 1791-1862
George Robert Charles, 13th Earl of Pembroke, 1850-1895
Sidney, 14th Earl of Pembroke, 1853-1913
Reginald, 15th Earl of Pembroke, 1880-1960
Sidney Charles, 16th Earl of Pembroke, 1906-1969 (Christie's, Wilton House, A Selected Portion of the Collection of
Ancient Marbles formed by Thomas 8th Earl of Pembroke, July 3rd, 1961, no. 52)
Vincent Korda (1897-1979), United Kingdom, acquired at the above sale
English private collection, by descent (Christie's, London, October 1st, 2014, no. 125, illus.)

James Kennedy, A Description of the Antiquities and Curiosities in Wilton House, Salisbury, 1769, p. 112 (“Black Marble-Table Room”)
George Richardson, Aedes Pembrochianae: or a critical account of the statues, bustos, relievos, paintings, medals, and other curiosities and antiquities at Wilton House, London, 1774, p. 113 of 1798 edition ("Passage to the Billiard Room")

The Greek inscription on the bust might have been commissioned by the 8th Earl himself, who was an enthusiastic antiquarian and to whom "it was a matter of pride that no head that entered his collection could be allowed to remain anonymous" (J. Scott, The Pleasures of Antiquity: British Collectors of Greece and Rome, New Haven, 2003, p. 43).

For a related bust also identified by a modern Greek inscription as Posidonius see Naples, inv. no. 6142; http://arachne.uni-koeln.de/item/objekt/13519 (G. M. A. Richter, The Portraits of the Greeks vol., London, 1965, p. 282, fig. 2020 [rev. ed. R.R.R. Smith, Oxford, 1984, pp. 189-1, fig. 150], St. Schmidt, in: P. Schultz – R. von den Hoff, ed., Early Hellenistic Portraiture. Image, Style, Context, Cambridge, 2007, 102, fig. 80, Ch. Vorster, “Die Plastik des späten Hellenismus – Porträts und rundplastische Gruppen,” in: P. C. Bol, ed., Die Griechische Bildhauerkunst III. Hellenistische Plastik, Mainz, 2007, pp. 281f., fig. 250, P. Zanker, Die Maske des Sokrates. Das Bild des Intellektuellen in der antiken Kunst, Munich, 1995, pp. 178ff., fig. 98, and A. Bottini, ed., Musa pensosa, 2006, p. 239, 254; no. 23).