Attalid dynasty
Born in Pergamon, probably in the early 50s, Aulus Julius Quadratus was the son of Aulus, and a wealthy patron of the city; his sister was named Julia Polla. Ronald Syme believed he was related to the general Gaius Julius Quadratus Bassus, although Quadratus was a member of the Roman tribe Voltina and Bassus belonged to the tribe Fabia. Olli Salomies has argued his family came from Gallia Narbonensis, while Weisser says that he was descended from the Attalid dynasty and the kings of Galatia.