Initiation into the Assassin Order

"Laa shay'a waqi'un moutlaq bale kouloun moumkine. The wisdom of our Creed is revealed through these words."

- Niccolò Machiavelli before Claudia Auditore's initiation.

The Initiation into the Assassin Order was a ceremonial tradition held within the Assassin Order. It was a rite of passage when an Assassin apprentice became a full member of the Order, and vowed to commit their life to safeguarding the freedom of humanity.

High Middle Ages
Although the full details of the initiation into the Order during the 12th century are unclear, the ceremony included the amputation of the ring finger, as a sign of commitment to the Creed. Afterwards, the hidden blade was installed, allowing the Assassin to participate in any assassination missions bestowed upon them.

As noted in the Codex of Altaïr Ibn-La'Ahad, some time after becoming a Mentor, Altaïr used the Apple of Eden to modify the design of the hidden blade, so that the amputation of the ring finger would not be necessary. This was done so an Assassin could not be as easily identified by a missing finger.

Renaissance
During the Renaissance, the initiation was performed by the Grand Master of the Order, alongside several other Assassins. The ceremony came in three parts, the speaking of the Creed, the branding of the initiate's left ring finger, and a Leap of Faith.

First, the participants stood around a lit brazier, with one Assassin reciting the Creed, which was answered in turn by the initiate. The final words, the maxim of the Creed, were spoken by all present.

Next, the initiate's left ring finger was branded with tongs that had been heated in the aforementioned brazier. This was a modification to the removal of the finger that Mario Auditore once commented on, saying that "In this modern age, we are not so literal as our ancestors, but our seal is no less permanent."

Finally, the initiate took a leap of faith - sometimes preceded by the Assassins present also taking a leap of faith - after which, the initiate was considered a full-fledged member of the Order.

Modern times
"Welcome to the Hashashin. Welcome to the Order of Assassins."

- The Mentor to Daniel Cross, 2000.

In modern times, the initiation had become much less formal and relevant. In 2000, the Mentor initiated Daniel Cross into the Order by rewarding him with an old hidden blade, and giving him a verbal welcome to the Order.

Trivia

 * Although Ezio's burn mark remains on his skin for the rest of Assassin's Creed II, it is not visible on his finger in Assassin's Creed: Brotherhood or Revelations