Colonial Brotherhood purge

"Sometime during the Seven Years' War the Templars made their move and destroyed [the Colonial Brotherhood] during the Assassin witch hunt."

- Shaun Hastings on the 1763 attack, 2012.

The 1763 attack was a full-scale assault on the Assassin Brotherhood in the British colonies by the Colonial Rite of the Templar Order, led by the Templar Grand Master, Haytham Kenway.

History
Following Haytham's arrival in the New World in 1754, the newly formed Colonial Rite quickly came into conflict with the already established Assassin Brotherhood in the region. Whilst initially a proxy war between the Templars and mercenaries recruited by the Assassins, the conflict soon intensified.

After nine years, the Templars launched their assault and attacked the Davenport Homestead; they killed all Assassins present, with the exception of their ageing Mentor, Achilles Davenport.

Convinced that the lone Assassin no longer posed a threat, the Templars spared Achilles' life, on the condition that he give up his life as an Assassin. Achilles agreed, and spent the next six years in complete isolation in his manor until the arrival of Ratonhnhaké:ton.

Reference

 * Assassin's Creed III