The Origin of Italian Surnames
This custom was lost in the Middle Ages, and individuals were known just with their baptismal name, as Gionata, Giuseppe, Simeone, until about the year 1000, when starting from Venice already a second name was added, to avoid confusion. The custom gradually spread from the nobility to all classes of people, and by the 15th century most surnames were formed. Finally in 1564 the Council of Trento ordered parish priests to record each individual with name and surname.
When it was necessary to distinguish individuals with the same Christian name, often the name of the father was added - Giovanni son of Berardo, which was shortened to Giovanni di Berardo or Giovanni Berardi, similarly to what happens in the English language with the suffix "-son". In the place of the father's name, especially if the father was not known by the community since the individual had come from another place, the toponymic could be used, as in Giovanni Calabrese or di Genova, or the job, as Mastro Giovanni.
His descendants then would often maintain this addition to the Christian name, giving origin to the present surnames. There is a great variety of surnames in Italy also because of the many dialects, the variations such as Grasso/Grassi (singular and plural), and the presence of derivatives consisting of a final suffix, "smaller" as in surnames ending in -ello, -etto, -ino; "bigger" (-one) or "bad" (- accio, - azzo). The following are the main classes of surnames:
Surnames listed alphabetically
Surnames divided by place