Different times. Most (being 2, brotherhood and revelations - all focused on ezio as shown here) are during the Renaissance. The first game was in medieval times during the crusades, the 3rd one is set during the American revolutionary War, the 4th is a bit before during the pirate era and unity is during the french revolution. And the one coming out is victorian london.
Wah I love how you make your backgrounds. It's like you design characters in a way for them to become figurines. Very dashing assassin. Looks more like a hero than a killer but nice design all the same. Is the cloak made of leather? Maybe some texturing could give it a more realistic texture.