* Ancient Origins: Gemini, along with many other constellations, has been recognized and named by ancient civilizations for thousands of years. The Babylonians, Greeks, and Egyptians all had their own myths and stories associated with the constellation.
* Star Patterns: Constellations are simply patterns of stars that humans have identified and given names to. These patterns have been visible since the beginning of time.
* Formal Recognition: While the ancient civilizations recognized the constellation, the International Astronomical Union (IAU) officially defined the boundaries of the constellation Gemini in 1930.
So, while the pattern of stars we call Gemini has been visible for ages, it was officially recognized and defined by the IAU in 1930.