The Italian law requires that your Italy-born Ancestor did not become a naturalized U.S. citizen (or citizen of any foreign country where he or she migrated to) before the birth of his or her son or daughter here in the U.S. Moreover, under the principle of “jure sanguinis," i.e. continuity of blood, you, as the applicant, have to demonstrate that the descendants of the Italy-born Ancestor did not renounce their rights to Italian citizenship.

A person with Italian dual citizenship is a citizen of two countries at the same time. While the United States allows dual citizenship without necessarily promoting it, not all countries do. Fortunately, Italy, along with Australia, Canada, UK, Ireland and a few others allow dual nationality without any restrictions. 

There are several ways to obtain dual citizenship with Italy: 

Errico (Errico being the Neapolitan version which was later changed to the Italian version Enrico) Caruso was born in Naples on February 25, 1873 in the house located in Via Santi Giovanni e Paolo, n. 7,  in the populated district known as  San Giovanniello, located between Piazza Ottocalli and Piazza Carlo III (picture below).

The “Mille” of Giuseppe Garibaldi, also known as the redshirts, were a thousand-people army (records disagree as to the exact number, what we know for sure is that a little over 1,080 made it to Sicily); despite scant preparations and a shortage of weapons, Garibaldi’s volunteers sailed from Quarto (dei Mille), a district of Genova, at dawn on May 6, 1860 and landed in Marsala a few days later. Against all odds and in less than three months, they conquered the entire island of Sicily, opening the way to a united Italy.