This is the inscribed base upon which a statue (now missing) representing the People of Judah was placed.
The Greek Inscription reads "Ethnous Ioudaion" = "The People of Judah."
For a close-up of the inscription Click Here.
This statue and base was one among 50 personified places and peoples (ethne) stretching from eastern Africa to western Spain that were under the control of the Roman Empire during the reign of Augustus (r. 27 B.C.–A.D. 14). They were placed on the second story of the north building of the Sebasteion. The idea, the list, and the images were borrowed directly from a monument in Rome.
Commentary from a description in the Aphrodisias' Museum.