A Roman Marble Amazonomachy Sarcophagus Fragment, Attica, 2nd quarter of the 3rd Century A.D.

carved in high relief with the figure of a Greek warrior fighting an amazon mounted on a rearing horse, the man holding a circular shield and wearing an Attic helmet, a rectangular mortise on top of the moulding; no restorations, remains of concrete and painted plaster along the perimeter suggesting that the fragment was once built into a wall.

Ugo Jandolo, Rome
Joseph Brummer (1883-1947), New York, inv. no. P13151, acquired from the above on November 19th, 1936, as "Found in the Sea, at Piraeus, in the beginning of the 19th Century" (http://libmma.contentdm.oclc.org/cdm/ref/collection/p16028coll9/id/40605)
The Cranbrook Academy of Art, Bloomfield Hills, Michigan, acquired from the above on June 2nd, 1938 (Sotheby Parke-Bernet, New York, The Cranbrook Collections, May 2nd-5th, 1972, no. 337, illus.)

Cornelius C. Vermeule, Greek Sculpture and Roman Taste, Ann Arbor, 1977, p. 12, fig. 10
The Gilgamesh Group Inaugural Exhibition, November 29- December 1, 1979, Setsu Gatodo Gallery 4F, Nihonbashi, Tokyo, no. 7, illus.
Theodosia Stefanidou-Tiveriou, Neoattika, Athens, 1979, p. 113, note 1
Guntram Koch and Hellmut Sichtermann, Römische Sarkophage, Munich, 1982, p. 391, note 3
Guntram Koch, "Einige Fragmente figurengeschmückter Sarkophage," Archäologischer Anzeiger, 1993, pp. 417ff., fig. 14
Carola Kintrup, "Chronologie der attischen Amazonomachie-Sarkophage," in Guntram Koch, ed., Akten des Symposiums "125 Jahre Sarkophag-Corpus" (Sarkophag-Studien, vol. 1), Mainz, 1998, p. 214, pl. 95,3
Carola Kintrup, Die attischen Sarkophage. Amazonomachie–Schlacht–Epinausimachie (Die antiken Sarkophagreliefs, vol. IX.1.2), Berlin, 2016, p. 83, and p. 262, no. 144, pl. 36,1.

Although the fragment shows water-induced corrosion, the reported findspot ("found in the sea, at Piraeus") is certainly a dealer’s invention to connect it with the famous "Piraeus-Reliefs“ found in 1930/31, not long before the present fragment appeared on the market.