February 2007 - There were rumors about a new X-COM game being developed by Irrational Games.
June 2010 - XCOM was officially revealed at E3 2010. It was announced as being developed by 2K Australia (now 2K Marin), which had split from Irrational Games, and that it would be a first-person shooter, as opposed to a strategy title.
Mid-2011 - XCOM was completely revamped.
In the intervening years, the game's release was pushed back several times - from 2011, to March 2012, to March 2013, to 2013-2014.