This is the tradition of Italian names. What you call De Di will give you an example. For example, Leonardo da Vinci's full name "Leonardo di ser Piero da Vinci" means "Leonardo." , the son of Piero, a native of Finch, is like this. When Italians give names, they must add who they are and where they come from. If you have played "Assassin's Creed", EZIO in it, his name is followed by Da Firenze, meaning the person from Florence