in Astrology, persons who erect horoscopes, or pretend to foretell what shall befall a man by means of the stars which presided at his nativity. The word is formed from the Greek γενήσις, origin, generation, activity. The ancients called them Chaldei, and also by the general name of mathematici; accordingly, the various civil and canon laws, which we find made against the mathematicians, only respect the genethliaci or astrologers. They were expelled from Rome by a formal decree of the senate, and yet found so much protection from the credulity of the people that they remained unmolested in the city. Hence an ancient author speaks of them as homines genus quod in civitate nostra semper et vetabitur et redibitur.