This research was funded by RSF, project number 23-28-01360. The paper is based on the study of the ancient tradition about the life and work of the prominent Roman administrator Tiberius Claudius Balbillus. His activities took place during the time of Claudius, Nero and Vespasian, and he was the head of the Alexandrian Museum and Library, procurator of Asia, governor of Egypt. For many years there has been a discussion about the identity or difference of this Balbillus with the astrologer Balbillus, mentioned by Suetonius (Suet. Nero 36) and Dion Cassius (Dio Cass. LXVI, 9, 2). We believe that it was the same person. He had a deep knowledge of astrology, but it was not his main field of activity. His proximity to the emperors was based not on horoscopes, but on personal friendship and great erudition. Besides, such figures could resist rumors about the imminent death of the emperor, which were often spread on Roman streets by all kinds of astrologers, prophets and miracle workers.