Byzantium was founded in the seventh century BCE as a Greek colony on the western shore of the Bosphoros. While individual Jews had occasionally attained Roman citizenship, most Jews became Roman citizens with the decree of Emperor Caracalla in 212. This citizenship characterized the status of the Jews in Byzantium until its conquest by the Ottomans and determined the status of the Greek speaking or Romaniote Jews of Istanbul under the Ottomans. Archaeological data and later references in the Theodosian and Justinianic codes attest to Jewish communities in North Africa where Jews had lived since Punic times. Jewish demographic expansion and demographic growth continued through the fourth century, when it began to be curtailed by the legitimization of Christianity and the latter's increasing attacks on the Jews. The lack of Hebrew inscriptions outside Palestine alongside the monumental Greek remains is one indication of the acculturating effect of the dominant Greek society.