Which Assassin's Creed game introduced the series' naval battle system as a major feature?

Assassin's Creed III introduced naval battles as a major feature in the Assassin's Creed series.

The game includes missions in which Connor Kenway commands the ship Aquila. Players steer the vessel, adjust its position, and fire cannons against enemy ships in battles set during the American Revolutionary War. These sequences became one of the game's most distinctive additions.

Naval gameplay had appeared in smaller forms before, but Assassin's Creed III made it a substantial, dedicated system. Assassin's Creed IV: Black Flag later expanded the concept dramatically, making ship travel and piracy central to its open-world design.

This distinction matters because Black Flag is often remembered as the series' defining naval game. It popularized and broadened a system that Assassin's Creed III first established as a major gameplay feature. Assassin's Creed III was released in 2012.