The development of BioShock Infinite began after BioShock's release in August 2007. The five-year development, led by studio Irrational Games, began under the moniker "Project Icarus". Irrational's creative lead, Ken Levine was inspired by events at the turn of the 20th century and the expansion of the concept of American Exceptionalism set by the 1893 World's Fair in Chicago. His story took these events to create a tale set in 1912 where the player, as former Pinkerton agent Booker DeWitt, is challenged to rescue a young woman, Elizabeth, who has been kept aboard the floating city of Columbia in the middle of a civil war between its founder Father Zachary Comstock and the Vox Populi, the underclass revolting against him.