Could it not be that Angiolo (also Angeolo) is actually a diminutive of Angelo? After all, -olo is an Italian masculine diminutive suffix. See also:- see page 33 of "Our Italian Surnames" written by Joseph Guerin Fucilla: https://books.google.de/books?id=Qmg6DfzFP9cC&pg=PA33 (in English; mentions that -olo is a diminutive suffix) - https://en.wiktionary.org/wiki/-olo#Italian (in English)
- see page 33 of "Our Italian Surnames" written by Joseph Guerin Fucilla: https://books.google.de/books?id=Qmg6DfzFP9cC&pg=PA33 (in English; mentions that -olo is a diminutive suffix)
- https://en.wiktionary.org/wiki/-olo#Italian (in English)