Firaxis Games Inc.
Firaxis was formed in 1996 by the three legendary game creators Sid Meier, Brian Reynolds and Jeff Briggs upon leaving MicroProse. Before forming Firaxis these three created some of the best classics of all times like Railroad Tycoon and the Civilization series at Microprose Software.
The company solely focuses on Sid Meier games, first with Sid Meier's Gettysburg!, Sid Meier's Alien Crossfire, and later Sid Meier's Pirates! (a remake), and the continuation of the main Civilization series with Sid Meier's Civilization III and IV