“…Italy has this really amazing thing called Jure Sanguinis that allows you to get dual citizenship if you can trace your ancestry back in a certain way. There’s some fairly complex rules to it, but in brief it says that if your immigrant ancestor had kids before he or she became an American citizen, then the kids were technically born as Italian citizens (according to Italy), and you are eligible to claim Italian citizenship as their descendant.”

https://blog.tomasino.org/moving-to-iceland.html#.VhEhWn0oeKI