Proteus was discovered from the images taken by Voyager 2 space probe two months before its Neptune flyby in August 1989. It received the temporary designation S/1989 N 1. Stephen P. Synnott and Bradford A. Smith announced its discovery on July 7, 1989, speaking only of "17 frames taken over 21 days", which gives a discovery date of sometime before June 16. Read more
Proteus, also known as Neptune VIII, is the second largest Neptunian moon, and Neptune's largest inner satellite. It is the largest known non-spherical moon in the solar system. It is named after Proteus, the shape-changing sea god of Greek mythology.
In Greek mythology, Proteus is an early sea-god, one of several deities whom Homer calls the "Old Man of the Sea", whose name suggests the "first", as protogonos is the "primordial" or the "firstborn".