Read this and answer the question. If the question is unanswerable, say "unanswerable".

In the everyday world, many individuals sought to divine the future, influence it through magic, or seek vengeance with help from "private" diviners. The state-sanctioned taking of auspices was a form of public divination with the intent of ascertaining the will of the gods, not foretelling the future. Secretive consultations between private diviners and their clients were thus suspect. So were divinatory techniques such as astrology when used for illicit, subversive or magical purposes. Astrologers and magicians were officially expelled from Rome at various times, notably in 139 BC and 33 BC. In 16 BC Tiberius expelled them under extreme penalty because an astrologer had predicted his death. "Egyptian rites" were particularly suspect: Augustus banned them within the pomerium to doubtful effect; Tiberius repeated and extended the ban with extreme force in AD 19. Despite several Imperial bans, magic and astrology persisted among all social classes. In the late 1st century AD, Tacitus observed that astrologers "would always be banned and always retained at Rome".

What group of people were several times expelled from Rome?
Astrologers and magicians