I have seen a quote that in the 1920's "Mandolin Makers were more common than Pizzerias in Italy". That may or may not be true but there were a lot of them and some of them turned their hand to making Ukuleles and Banjoleles as well. Unfortunately there is not a lot of information on most of them beyond the paper label in the sound hole. Here is the ones I have seen so far, with any other information I have found on them
The label reads, " G. Bianchi premiata fabbrica di strumenti musicali a corda" which translates to "award-winning factory stringed musical instruments" and I have no further information, not even a location?
Founded in Napoli (Naples) in 1895 this was a very famous and good Mandolin maker. Good enough be the official maker for the Italian royal family at the time, (and including the coat of arms for the House of Savoy), and good enough as a Mandolin maker to be widely copied so having to include a lot of early copyright type notices on the label.
Giovanni de Meglio was the founder and some later family members were Gherado and Vincenzo but I don't know the relationships. It is the case though with the number of instruments made that this was bigger than just a family workshop. One of the distinguishing traits of their instrument was the ornate sound hole embellishments. I don't know when production ceased but they don't appear to have survived much past 1930?
From Naples and imported by J T C - L , the same company that distributed Down Souths and Handels
From Catania, Sicily according to the label and I have no further information
From Savona - Founded in 1840 and more famous for Violins