From everything I've heard and read, the Italians have always been big into nicknames, which I've always found fascinating, because for most of my life I've lived among people who don't use nicknames at all. (The only "community" where I and others have nicknames is my immediate family circle, which doesn't really count, because we don't use those nicknames publicly.)
There are plenty of examples of the Italian genius for bestowing nicknames in Vasari. One reason nicknames may have been so prevalent is because they were necessary: assuming the translation is accurate, Vasari only rarely refers to people by their surnames, preferring to use their first names instead. And if everyone else in Italy did the same, then nicknames would definitely help the Italians keep straight who was who, given that were so many Giovannis, Paolos, Giambattistas, etc.
Sidebar: it seems to me that in every language there are a handful of names that are somewhat baffling and unique to that language. For instance, in French there's the girl's name "Marie-France". Maybe it's derived from "Mary Frances", but they do have "Françoise" for "Frances", so "Marie-France" might be nothing more than a concatenation of "Mary" and "France". And if that's true... what's up with that???
Similarly, there's the way that French and Italian (and probably other Romance languages, too) have made a personal name out of the name of St. John the Baptist: "Jean-Baptiste" in French, and "Giambattista" in Italian. But think how strange it would sound in English if there were people named "Johnbaptist". Without that connective "the", it comes off as primitive... but with the connective "the", it seems too specific to be applied to anyone other than the person who originally had that name. "I named my son 'John the Baptist'... You know, after John the Baptist." Or it would be like naming your son "President Washington" instead of "George Washington".
The other Italian name that strikes me as odd and unique is "Michelangelo". Again, it sounds so strange in English: "Michael Angel". Again, there's the problem of the connective "the". Also, I have to wonder why Italian doesn't have similar names for other famous angels, like "Gabrielangelo" and "Rafaellangelo". Why should only Michael get the suffix? An unsolvable mystery, no doubt.
Anyway, on with the quotes. Here are two specimens of nicknames based on one's lifework:Vol. I, p. 758, Simone, called Il Cronaca: Thereupon he conceived the idea of returning to Florence, and departed from Rome; and on arriving in his native city, having become a passing good master of words, he described the marvels of Rome and of other places with such accuracy, that from that time onwards he was called Il Cronaca, every man thinking that he was truly a chronicle of information in his discourse.
Vol. II, p. 45, Fra Giocondo, Liberale, and others: The elder Francesco dai Libri of Verona ... was called "Dai Libri" [of the books] because he practised the art of illuminating books ...
Two more, among many others that could be chosen, that show apprentices' surnames being changed to that of their masters, in an organic and logical way:Vol. II, pp. 153 - 5, Perino del Vaga: [Perino] was taken as shop-boy by the painter Andrea de' Ceri, who ... was wont to paint every year for the festival of S. John certain wax tapers which were carried at the offerings, as they still are ... for which reason he was called Andrea de' Ceri [wax], and from that name Perino was afterwards called for some time Perino de' Ceri. ... [But then: ] There came to Florence at that time the Florentine painter Vaga ... [who] recommended [Perino] to all the friends that he had ... from which circumstance he was always called from that day onward Perino del Vaga.
Vol. II, p. 804, Jacopo Sansovino: And such were the reciprocal friendliness and love between these two [Andrea Contucci, called "Sansovino", and Jacopo Tatti], as it were between father and son, that Jacopo in those early years began to be called no longer Tatti, but Sansovino, and so he has always been, and always will be.
Speaking of painting wax tapers: at our neighborhood PathMark (a local grocery store chain), you can buy votive candles with saints' portraits on them. The candles have bilingual inscriptions, but are clearly aimed at Hispanics. It's an interesting thing to realize that while we generally think of painting and photography as being equally able to depict a person's likeness, it's inconceivable for these candles, or other devotional art, to feature photos of people dressed up as these historic saints.
No, somehow, painting (or sculpture) is the only way to depict the old saints, even though many artists throughout history have painted portraits of saints from live models -- including themselves. My guess for why photography isn't appropriate is that something like Scott McCloud's theory of "identification" is at work here: just as a simple cartoon face can stand for anyone's face, so too can a generically drawn saint's face be "universal" enough to depict an unknowable person. A painter can "genericize" a person's face by simply choosing not to depict all of its details and features; but you can't do that with photography, not easily anyway; and even if you could, the result would probably be kind of creepy, like the animated figures in The Polar Express...
Incidentally, I've read that the reason why Eastern Orthodox icons all look the same is because they're believed to be like divine photographs -- they are what the saints look like, and every icon painter has imitated the icons that came before so as not to lose anything of the sacred images that were first painted by St. Luke.
But getting back to surnames in Renaissance Italy, here's a quote that illustrates the marvellous fluidity of surnames in an era before modern bureaucracy and social security numbers:Vol. II, p. 486, Giovanni da Udine: In Udine, a city of Friuli, lived a citizen called Giovanni, of the family of the Nanni, who was the first of that family to give attention to the practice of embroidery, in which his descendants afterwards followed him with such excellence, that their house was called no longer De' Nanni but De' Ricamatori ["the Embroiderers"].
This one gives a nickname for a painting rather than a painter:Vol. II, p. 123, Giulio Romano: Then ... Giulio painted a picture of Our Lady, with a cat that was no natural that it appeared to be truly alive; whence that picture was called the Picture of the Cat.
I like this quote because it also shows how formal titles for artworks were mostly lacking in those days. After all, what need for a title is there for a portrait of the Madonna and child, surrounded by SS. Barbara, Catherine, and Zenobius?
And, by the way, after years of seeing pictures like that in museums and churches, the whole concept finally struck me as strange while I was reading Vasari. Having adult saints from future ages looking adoringly down on the infant Christ now seems kind of odd to me: both because of the chronological distortion, and also because it seems to somehow elevate the saints over the Messiah: they're the grown-ups and he's the baby (despite being one-third of the Supreme Being). Obviously, the original intention was something like "Saints of all eras have adored the purity of his birth", but I do think it's a rather strange juxtaposition all the same.