Around the time Ezio faced off with Cesare in Spain, an exceedingly handsome young man came into the household of Leonardo da Vinci, who gladly sheltered him.
Leonardo attributed all that running about the rooftops as something overly energetic young men do. And he must have been getting on in years to find memories of another young man while looking at his new apprentice's back.
It was when Giovan Francesco Melzi used Eagle Vision, that Leonardo realized perhaps Francesco was not really Girolamo Melzi's son as the boy originally claimed.
tldr version: *Melzi uses Eagle Vision.* Leonardo: Dear God Ezio how many bastard children do you have? And why am I paying child support for this one?
Not the son of a Milanese noble family
Leonardo attributed all that running about the rooftops as something overly energetic young men do. And he must have been getting on in years to find memories of another young man while looking at his new apprentice's back.
It was when Giovan Francesco Melzi used Eagle Vision, that Leonardo realized perhaps Francesco was not really Girolamo Melzi's son as the boy originally claimed.
tldr version:
*Melzi uses Eagle Vision.*
Leonardo: Dear God Ezio how many bastard children do you have? And why am I paying child support for this one?