Syrian city on caravan route from the eastern Mediterranean to the Euphrates; an ancient oasis town. Occupation was probably continuous since the 3rd millennium BC, but the town achieved prominence in the 1st century BC by exploitation of the caravan trade. Under Roman influence of Septimus Severus, it gained the status of a colony. A temple to Baal (Bel) dedicated in 32 AD, colonnaded streets, agora, senate house, and headquarters building of fort by Diocletian have been found. Communal tower tombs (hypogea) were marked by relief plaques naming the deceased. Its monuments which blend Greek, Roman and Parthian traditions and art.