Which Assassin's Creed game first introduced the series' modern naval exploration system?

Assassin's Creed III first introduced the Assassin's Creed series' modern naval exploration system.

Released in 2012, Assassin's Creed III added naval missions in which Connor commands the ship Aquila. These sequences include steering, managing sails, firing cannons, and fighting enemy vessels in coastal waters.

The naval feature was initially part of a broader American Revolution setting rather than the entire game. Players could visit the North Atlantic and undertake missions separate from the main land-based cities and frontier areas.

Assassin's Creed IV: Black Flag later made naval travel and piracy the central focus, so it is often mistakenly credited with introducing the system. Black Flag greatly expanded the idea with open Caribbean sailing, ship upgrades, treasure hunting, and underwater exploration. Assassin's Creed III nevertheless established the modern series' ship-combat foundation.