Washington's Battle Sword (replica)
Although it's nothing but a replica of the real thing, George Washington's colichemadre sword is the most powerful sword in Assassin's Creed III. Washington can be seen carrying the real deal in game. It is a hanger-type sword forged of steel with a grooved blade with a grip of green dyed ivory with a silver strip decoration. It came with a leather scabbard with a silver trim. Connor can only possess this sword by crafting it. To craft it, Connor must require silver ore and special iron ingot.
Trivia
The authentic sword was inherited by Washington’s nephew, Samuel T. Washington, an army captain. In his will, Washington admonished his nephew to draw the sword only "in self-defense or in the defense of [the] country and its rights.” Samuel's son donated the sword to the United States government in 1843.