In Greece and Rome astrology proper ceased to have the importance in augury which it had maintained in Chaldea, while, as the word augury (avigerium) itself would indicate, the preeminence had been given to omens taken from the flight of birds. Both among the Greeks and Romans much of the art of augury depended on the cardinal points of the compass. The Greek augurs always faced the north, while the Roman augurs faced the south. Omens in the east were generally lucky, while those in the west were unlucky. Hence the Greek had his right hand synonymous with good fortune, the Roman originally his left. Later in Roman history, however, sinister (left) became a synonyme for bad fortune, and dexter (right) for good. Auguries were made both from the flight and cries of birds. Lightning was also observed by the augurs, as well as other striking phenomena, such as meteors, winds, and eclipses. The direction in which a bird flew, the crowing of a cock, the line of the electric flash, and the manner in which a cooped chicken picked his corn, were prominent angaria) elements. Some even more trivial and accidental occurrences were reckoned ominous, such as an animal crossing one's path, a fit of sneezing or sudden melancholy, the spilling of salt on the table, or of wine upon one's clothes.
The power of the Greek and Roman augurs was very great. They held their offices for life, regardless of character. In Rome they were at first three in number, and were chosen one from each of the three tribes of the patricians. They were elected by the comitia curiata, a patrician assembly, until the Ogulnian law (300 B. C.) admitted the plebeians and enlarged the number of augurs, then four, to nine, subsequently increased to 15. Every election had to be ratified by the college itself. This original power of veto afterward resulted in the usurpation by the college of the right to elect its own members by cooptation (452 B. C), which right they retained, with the exception of the first election of plebeian augurs, for 348 years, until the passage of the Domitian law (104), which removed the power of election to the tribes. The most authoritative enactments of the comitia were repeatedly annulled by the entrance of an augur into the assembly, pronouncing the words Alio die ("On another day"). The order of augurs gradually declined after the admission of the plebeian element, until it was abolished, with paganism in general, by Theodosins the Great, about A. D. 390.