The Great Purge (1757–1763) was a full-scale assault on the Colonial Brotherhood of Assassins in the Thirteen Colonies by the Colonial Rite of the Templar Order, led by Grand Master Haytham Kenway.
Before Haytham arrived in the colonies, the Colonial Brotherhood under the Mentor Achilles Davenport controlled the Atlantic coast of North America. They used gangs as enforcers, and ruled a number of forts and settlements. The Assassins also possessed an established network of spies and allies. As such, they were more powerful than the Templars in the area. In 1752, the high-ranking Templars Lawrence Washington, Samuel Smith, and James Wardrop, were assassinated after stealing the Precursor box and Voynich manuscript from the Assassins in Saint-Domingue following an earthquake a year prior.
In 1754, following Haytham's arrival in the New World, and the formation of an independent Colonial Rite, the resurgent Templars quickly came into conflict with the well-established Assassins. Beginning as a proxy war between the Templars and mercenaries recruited by the Assassins, the conflict escalated when the two factions sided with opposing European powers during the Seven Years' War.
Turning the tide
From 1757 onward, Shay Cormac, a former Assassin, helped the Templars track down and kill several of his former comrades, including the high-ranking Assassins Kesegowaase, Hope Jensen, and Chevalier de la Vérendrye. In addition to his former colonial brothers, Shay also eliminated Adéwalé, a legendary member of the Caribbean Brotherhood.
Shay also used his ship the Morrigan, a heavily modified sloop-of-war, to cripple the Assassin navy. Among the ships which fell victim to his actions were Adéwalé's vessel, the Experto Crede, and the Gerfaut captained by Chevalier de la Vérendrye. Shay also managed to sink the Storm Fortress, the flagship of the Assassin navy.
Furthermore, Shay also eliminated seven Assassin-allied gangs in New York, liberated several forts in the River Valley and along the Atlantic coast, intercepted several Assassins during their missions, and killed a number of stalkers sent after him personally, weakening the Assassin presence further.
In 1760, in a battle at a Precursor Temple in the Arctic, the Brotherhood's leadership was broken. The high-ranking Assassin Liam O'Brien was killed, and the Mentor Achilles Davenport was crippled by Haytham. Thereafter, the Brotherhood's influence in the Colonies was severely diminished and they were left on the brink of destruction, while the power of the Templars continued to grow. Confident that he was no longer a threat, the Templars spared Achilles' life, on the condition that the Assassins stop searching for First Civilization sites.
In 1763, three years after the Assassins' defeat at the Arctic, the Templars launched their final attack on the Davenport Homestead, killing all of the remaining Assassins save for Achilles and Robert Faulkner. Convinced that the lone Mentor no longer posed any threat, the Templars spared Achilles' life once again, this time on the condition that he give up his life as an Assassin.
However, some Assassins survived the purge, such as Benjamin Tallmadge, who went into hiding. Pierre Bellec, who was training in the colonies at the time, left for France before the Templars could claim his life. Nevertheless, the ruthless acts committed by Haytham during the purge had a lasting effect on Bellec, who claimed to have seen the Templars "put entire villages to the sword, just for the chance of killing one Assassin". These experiences deepened his hatred for the Templar Order and made him resistant to the very idea of the truces proposed by Mentor Mirabeau or his own student, Arno Dorian.
A depressed and embittered Achilles would spend the next six years in isolation at his manor, allowing it to fall into disrepair. It wasn't until the arrival of Haytham's son, Ratonhnhaké:ton, that the Colonial Brotherhood would rise from the ashes. Under Achilles' training, Ratonhnhake:ton would go on to exterminate the Colonial Templar Rite and rebuild the Colonial Assassins, making them stronger than ever.
- Assassin's Creed III (mentioned only)
- Assassin's Creed: Forsaken (mentioned only)
- Assassin's Creed: Rogue (first appearance)
- Assassin's Creed: Unity (mentioned only)
- Assassin's Creed: Infographics
- Assassin's Creed: Rogue – 
- Assassin's Creed III – Database: Achilles Davenport
- Assassin's Creed III – Database: Davenport Homestead
- Assassin's Creed III – Database: Robert Faulkner
- Assassin's Creed III – Something on the Side
- Assassin's Creed: Unity – Database: Pierre Bellec
- Assassin's Creed: Unity – Graduation
- Assassin's Creed: Unity – A Cautious Alliance
- Assassin's Creed III – A Boorish Man
- Assassin's Creed III