He is what is generally known as a Maremma sheepdog, although here where the breed originates (and not in Tuscany) folk get aggrieved if it is not called an Abbruzzese sheepdog.
This was my previous one, we actually bought him while still in Britain and then promptly brought him to Abruzzo, then once here we got the Scottish Collie! At least we are consistent in our irrational behavour