Which game introduced the AnvilNext engine to the Assassin's Creed series?

Assassin's Creed III introduced the AnvilNext engine to the Assassin's Creed series.

Released in 2012, Assassin's Creed III was built with AnvilNext, an updated version of Ubisoft's technology for rendering environments, crowds, animation, and large-scale action. The engine supported the game's frontier landscapes, colonial towns, naval sequences, and dense crowds during the American Revolution.

The game stars Ratonhnhaké:ton, commonly called Connor, and covers events from the eighteenth century. Its setting includes Boston, New York, and the surrounding frontier. Connor's story intersects with the American Revolution and with the continuing Assassin-Templar conflict.

AnvilNext should not be confused with later engine revisions or with individual game titles. Assassin's Creed Unity, for example, used an updated version called AnvilNext 2.0. The original introduction of the AnvilNext engine belongs to Assassin's Creed III, which marked a major technical transition for the franchise.