Where do you get the Dark Oracle's Bone Dagger in Assassins Creed 2?

In Assassin's Creed II, the Dark Oracle's Bone Dagger is obtained by completing the "The Truth" quest. After collecting all the pieces of the "Codex" and solving the puzzles, you unlock the hidden chamber where the dagger is located. It's part of the secret storyline that delves into the background of the First Civilization. To find it, players must navigate through the chamber and claim the weapon as a reward for their efforts.