In 1775, the Assassin Connor sent his apprentices to investigate Templar presence in Montreal. They learned that the Templars had seized control of the city's port, and were ordered to relieve them of their ownership.
In 1832, the journalist and secret Assassin Ludger Duvernay posted several articles accusing the Canadian administration of serving the Château Clique, the leaders of the Templars. Duvernay was arrested and imprisoned on charges of spreading false information, but he was quickly freed by the Assassins.
On 24 June 1834, Duvernay hosted a soirée for his secret society, the Saint-Jean-Baptiste Society, to rally against his enemies. However, a Templar agent infiltrated the party posing as a violist, and killed one of Duvernay's allies, only to be knocked out by Larose.
In 2013, Abstergo Entertainment, the media arm of business conglomerate Abstergo Industries, had a facility in the city. Its employees were tasked with reviewing the memories of various individuals' ancestors, including Aveline de Grandpré, Edward Kenway, and Shay Cormac.