The Ivalice Alliance is a series of video games that take place in the Final Fantasy series. Each game takes place in Ivalice, which is unique as most games in the Final Fantasy series take place in distinct areas from each other. Many games took place in Ivalice before the alliance was created, and thus those games aren't officially part of the alliance.
The Ivalice Alliance was announced on December 13 of 2006 when Square Enix reported that the already announced Revenant Wings would accompany a host of other games in a series of games called the Ivalice Alliance. These other games included Final Fantasy Tactics A2: Grimoire of the Rift for the Nintendo DS and The War of Lions for the PSP.