Surnames did not arise in Trentino until sometime during the early to mid 1500’s — moreso after the 1564 Council of Trent which ordered use of surnames for each individual. Until the use of surnames, a person was generally known by his first name and a reference to his father (I am not sure if this was true for females as well). For example, “Giuseppe, di Francesco” or “Giuseppe, son of Francesco”.
Given the fact that there were not very many first names in use, this method of identification proved very awkward as village populations increased. As an extension of the above father-son method of assigning surnames, early surnames were often developed by using a combination of the person’ s first name and father’s first name. Thus, in this example, Giuseppe would become known as Giuseppe Difrancesco.
Surnames also developed based on first names only, which were often based on early Latin versions, e.g.
Pinamontus —> Pinamonti
Endrigi —> Endrizzi
Petrus/Pietro —> Pedri, Pedron
Matteus —> Mattevi
Surnames were also developed based on a personal characteristic, residence, occupation, etc. Examples:
Rossi = a person with red hair
Rizzi = a person with curly hair
Torresani and Dallatorre = a person who owned, lived, worked, etc in a tower (“torre“)
Sartori = person who was a tailor
Name Changes in America
Often, when emigrating to the US, a person’s name was “Americanized” – sometimes by choice, sometimes due to handwriting, sometimes due to pronunciation (for example, the letter “i” is pronounced “eee” in Italian, the combination “ch” is pronounced like the English “K” which is very rarely found in Italian writings). Because of the pronunciation by immigrants upon their boarding a ship in Europe or arriving at Ellis Island, it was common for immigration officials to write surnames phonetically as pronounced by the immigrant. Most of the manifests were written at the departure point (for emigrants from Trentino one of the main departure points was Le Havre, France). This practice has been a stumbling block to many researchers trying to find their ancestors’ ship arrival manifests.
Name changes I have seen include:
Covi —-> Covey
Chini —-> Kinney, Keenay
Ferrari —-> Ferrary
Iob or Job —-> Yob, Jobe
Stancher —-> Stanker
Bertagnolli —-> Berry (apparently a voluntary change)
Battocletti —-> Bartley
Franch —-> Frank, Franks
Vielmetti —-> Wilmetti