The General Rule
In order to demonstrate that you have inherited a right to citizenship by descent, you must demonstrate that citizenship was transmitted from his or her Italian-born ascendant to the applicant.
Italian citizenship was exclusive until 15 August 1992; therefore, the voluntary acquisition of any non-Italian citizenship meant the automatic renunciation of one’s Italian citizenship for people who were born with Italian citizenship. Children born to Italian citizens in the United States or other countries with jure solis, however, acquired their foreign citizenships involuntarily because of their birthplaces. Ergo, these children can claim citizenship by descent if and only if they can prove that their Italian-born ascendant was an Italian citizen at the moment of their births. Subsequently, they can pass citizenship onto their children, grandchildren, etc., barring a loss of citizenship somewhere along the line.
Italy has been a participant in the Strasbourg convention on the reduction of cases of multiple citizenship.
There were no Italian citizens prior to 17 March 1861, because Italy did not exist as a nation. Thus the oldest Italian ancestor in any jus sanguinis citizenship application must have been still alive on or after that date.
Any child born to an Italian citizen parent (or parent also with the right to Italian citizenship jus sanguinis) is ordinarily born an Italian citizen, with the following caveats: If the child was born before 15 August 1992, the Italian parent ordinarily must not have naturalised as a citizen of another country before the child’s birth.
Before you can find out if you qualify for Italian citizenship jure sanguinis, you should know:
• The birth dates of every relative in a direct line between you and your ancestor from Italy. It’s OK if you don’t have exact dates right now, but you should at least know the year.
• The date your ancestor from Italy became a naturalized citizen of your country.
Before you start the process of obtaining dual citizenship, you should also find out whether acquiring Italian citizenship will affect your current citizenship by checking with the nearest Italian authority and/or consulting your government’s citizenship laws.