In The Da Vinci Code, Robert Langdon refers to Leonardo as "Da Vinci." Right away, beginning with this book's title, I began to squirm. If fictional Harvard professors like Robert Langdon – who certainly, being Harvard professors, should know better - were to begin calling the artist "Da Vinci," I feared there was little hope for the rest of us mere mortals. Sure enough, since the novel's publication one sees reporter after author after blogger referring to Leonardo as "Da Vinci."
Let's get this straight.
Leonardo's full name at birth was simply Leonardo. As an illegitimate child, he was fortunate that his father, Ser Piero, acknowledged him and let him be known as Leonardo di ser Piero. (Ser Piero was a bit of ladies' man, it seems. Leonardo was his eldest child, begat of Caterina, a servant girl. Ser Piero went on to become a notary, marry four times and sire nine more sons and two daughters.)
Leonardo was born in Anchiano, a tiny hamlet near the slightly-larger hamlet of Vinci. Ser Piero's family, however, were big fish in the little Vinci pond, and so tagged "da Vinci" ("of" or "from Vinci") after their names.
When he became an apprentice, in order to distinguish himself from other various Tuscan Leonardos in 15th-century Florence, and because he had his father's blessing to do so, Leonardo was known as "Leonardo da Vinci." When he traveled beyond the Republic of Florence to Milan, he often referred to himself as "Leonardo the Florentine." But "Leonardo da Vinci" continued to stick with him, whether he'd wanted it to or not.
Now, we all know what happened after this. Eventually, Leonardo became very famous. As famous as he was in his lifetime, his fame kept snowballing after his death in 1519. He became so famous, in fact, that for the past 500 years he has had no need of a last name (as with "Cher" or "Madonna"), let alone any indication of his father's home town.
In art historic circles he is simply, as he started out in this world, Leonardo. The "Le-" part is pronounced "Lay-." Any other Leonardo needs a surname slapped on, up to and including "DiCaprio." There is but one "Leonardo," though - and I have yet to hear of his being referred to by name as "Da Vinci" in any art historic publication, course syllabus or textbook.
"Da Vinci," then as now, indicates "from Vinci" – a distinction shared by many thousands of people born and raised in Vinci. If one felt utterly compelled, say, at gunpoint, to use "Da Vinci," he or she would need to be certain to write "da" (the "d" is not capitalized) and "Vinci" as two separate words.
This all being said, it must be acknowledged that The Leonardo Code hasn't got nearly as snappy a ring to it as the book's real title.