Aquila (the Eagle) is one of the 48 constellations listed by Ptolemy, also mentioned by Eudoxus of Cnidus (fourth century BC.) And Aratus (third century BC.), And currently one of the 88 constellations recognized by the IAU. Ptolemy cataloged nineteen stars jointly in this constellation and the constellation of Antinous, the latter emerged during the reign of Hadrian (117-138 AD.). It occupied the southern part of the current constellation of Aquila until the early nineteenth century, when it was discarded.