The following is an excerpt from "Lives of the Most Eminent Painters Sculptors and Architects, Vol. I" by Giorgio Vasari, originally published in 1550:

That very obligation which the craftsmen of painting owe to nature, who serves continually as model to those who are ever wresting the good from her best and most beautiful features and striving to counterfeit and to imitate her, should be owed, in my belief, to Giotto, painter of Florence, for the reason that, after the methods of good paintings and their outlines had lain buried for so many years under the ruins of the wars, he alone, although born among inept craftsmen, by the gift of God revived that art, which had come to a grievous pass, and brought it to such a form as could be called good. And truly it was a very great miracle that that age, gross and inept, should have had strength to work in Giotto in a fashion so masterly, that design, whereof the men of those times had little or no knowledge, was restored completely to life by means of him. And yet this great man was born at the village of Vespignano, in the district of Florence, fourteen miles distant from that city, in the year 1276, from a father named Bondone, a tiller of the soil and a simple fellow. He, having had this son, to whom he gave the name Giotto, reared him conformably to his condition; and when he had come to the age of ten, he showed in all his actions, although childish still, a vivacity and readiness of intelligence much out of the ordinary, which rendered him dear not only to his father but to all those also who knew him, both in the village and beyond.

Now Bondone gave some sheep into his charge, and he, going about the holding, now in one part and now in another, to graze them, and impelled by a natural inclination to the art of design, was for ever drawing, on stones, on the ground, or on sand, something from nature, or in truth anything that came into his fancy. Wherefore Cimabue, going one day on some business of his own from Florence to Vespignano, found Giotto, while his sheep were browsing, portraying a sheep from nature on a flat and polished slab, with a stone slightly pointed, without having learnt any method of doing this from others, but only from nature; whence Cimabue, standing fast all in a marvel, asked him if he wished to go to live with him. The child answered that, his father consenting, he would go willingly. Cimabue then asking this from Bondone, the latter lovingly granted it to him, and was content that he should take the boy with him to Florence; whither having come, in a short time, assisted by nature and taught by Cimabue, the child not only equalled the manner of his master, but became so good an imitator of nature that he banished completely that rude Greek manner and revived the modern and good art of painting, introducing the portraying well from nature of living people, which had not been used for more than two hundred years. If, indeed, anyone had tried it, as has been said above, he had not succeeded very happily, nor as well by a great measure as Giotto, who portrayed among others, as is still seen to-day in the Chapel of the Palace of the Podestà at Florence, Dante Alighieri, a contemporary and his very great friend, and no less famous as poet than was in the same times Giotto as painter, so much praised by Messer Giovanni Boccaccio in the preface to the story of Messer Forese da Rabatta and of Giotto the painter himself. In the same chapel are the portraits, likewise by the same man’s hand, of Ser Brunetto Latini, master of Dante, and of Messer Corso Donati, a great citizen of those times.