Live by the Creed: Assassin's Book Idea

Assassin's Creed II is amazing. So much that it inspired me to write, and I've only played a demo. The game's plot is great and the gameplay is smooth. the story is about Ezio Auditore Di Firenze, the son of an italian banker during the Italian Renaissance. The Auditore Di Firenze are descendants of a long line of assassin's. One day, Giovani Auditore, Ezio's father, is hanged for treason. Framed. the Auditores tried to defend Medici, not attempt his murder. So, Ezio dons his fathers assassin's robes and vows revenge.

I love the story, so I want to write one with the main character based on Ezio. An assassin novel. But at what time? The Renaissance? I was thinking sometime during Feudal Japan, or during WWII. I also need a title.