Civilization IV (also known as Sid Meier's Civilization IV) is a 4X turn-based strategy computer game and the fourth installment of the Civilization series, and designed by Soren Johnson under the direction of Sid Meier and his video game development studio Firaxis Games. It was released in North America, Europe, and Australia, between October 25 and November 4, 2005, and followed by Civilization V.