Legio decima Gemina ("The Twins' Tenth Legion"), was a legion of the Imperial Roman army. It was one of the four legions used by Julius Caesar in 58 BC, for his invasion of Gaul. There are still records of the X Gemina in Vienna in the beginning of the 5th century. The legion symbol was a bull. Early on in its history, the legion was called X Equestris (mounted), because Caesar once used the legionaries as cavalry.