The History of Vampire (Part 2)

The First Vampire Clan

Ambrogio later moved back to Italy, now as a full-fledged vampire. Legend traces him to the city of Florence (Firenze), where he creates the first Vampire Clan.
We don't know a whole lot about this clan, other than they were most likely willing volunteers - humans who wanted power and immortality, and were willing to trade their souls for it. It was believed that the curse would continue for any vampire where their souls would remain in the Underworld (aka Hades aka Hell), where they could return to claim them, but then could never leave.
From what we know of the history of vampires, the clan grew in size and strength, until infighting created something of a "civil war" within the clan, and many vampires left to form their own clans.
What happened to Ambrogio and those who stayed with him is largely unknown, though many believe that he still resides somewhere in Florence.


Source: http://www.gods-and-monsters.com/history-of-vampires.html