- Shay: "Anticosti is famed for its shipwrecks. They likely believe no one would venture into such dangerous waters."
- Gist: "None but fools and madmen, perhaps? Watch out for those icebergs, Captain."
- —Shay and Gist regarding Anticosti, 1759.[src]
The island was first discovered in 1534 by the French explorer Jacques Cartier, who named it Isle d'Assomption. By the 17th century, however, this name fell into disuse, with the island instead being referred to as Anticosti, in an attempt to mimic the name used by the indigenous people of the area.
In 1680, King Louis XIV of France handed the island to Louis Jolliet, making Anticosti the largest island in the world to ever be privately owned. Jolliet subsequently erected a fort for his family on the island. In spite of its size, Anticosti never became particularly well-populated, likely due to its treacherous coastline; over 400 ships would wreck themselves on the rocks and reefs surrounding the island, leading people to nickname it "The Cemetery of the Gulf".
By the 1750s, the dilapidated fortress was being used by a band of pirates, with whom Le Chasseur, a spy allied with the Assassins, associated. In April 1752, Assassins Chevalier de la Vérendrye, Liam O'Brien and Shay Cormac sailed to Anticosti, where they would meet with Le Chasseur to discuss their search for the Precursor box and the Voynich manuscript.
Shay, having defected from the Assassins to join the Templars, returned to Anticosti in 1759, intent on assassinating de la Vérendrye and preventing the Assassins' expedition to another Isu temple. As de la Vérendrye had already departed, Shay stole maps detailing the Assassins' destination and then departed as well. He would later return to claim the fort for the Royal Navy.