Improbable murderer

From: Detective
Description: To obtain the diadem, you must join all of the Borgia treasures together.
Completed: Impossible! How can Cesare Borgia himself be the murderer?! I've seen many things here but this shocks even me. Cesare must have been drawn to the City from his own time, simultaneously with that plane. Then he starts his new life poisoning and stabbing an innocent man. This proves that, in the City, all your personality traits, vices and virtues, talents and sins gain a renewed strength.