The premise is simple but has become timeworn: you take a faction from Stone Age primitivism to either global conquest or interplanetary colonization. While there had been earlier games that incorporated many of the features, such as conquest, tech trees, and city management, Sid Meier's landmark game brought them all together and with the necessary oomph and flair to appeal to a large demographic beyond just wargamers that gave it a staying power as one of the most dominant and recognizable PC franchises in history.
Sid Meier's Civilization was a watershed for the 4x genre before the genre even had its present name.
