Vasari's Lives of the Artists Chapter IX: Masaccio.

The Life of Masaccio from San Giovanni di Valdarno, Painter
[1401 - 1428]

"It is the custom of nature, when she makes a man very excellent in any profession, very often not to make him alone, but at the same time, and in the same neighbourhood, to make another to compete with him, to the end that they may assist each other by their talent and emulation; which circumstance, besides the singular advantage enjoyed by the men themselves, who thus compete with each other, also kindles beyond measure the minds of those who come after that age, to strive with all study and all industry to attain to that honour and that glorious reputation which they hear highly extolled without ceasing in those who have passed away. And that this is true we see from the fact that Florence produced in one and the same age Filippo, Donato, Lorenzo, Paolo Uccello, and Masaccio, each most excellent in his own kind, and thus not only swept away the rough and rude manners that had prevailed up to that time, but incited and kindled so greatly, by reason of the beautiful works of these men, the minds of those who came after, that the work of those professions has been brought to that grandeur and to that perfection which are seen in our own times. Wherefore, in truth, we owe a great obligation to those early craftsmen who showed to us, by means of their labours, the true way to climb to the greatest height; and with regard to the good manner of painting, we are indebted above all to Masaccio, seeing that he, as one desirous of acquiring fame, perceived that painting is nothing but the counterfeiting of all the things of nature, vividly and simply, with drawing and with colours, even as she produced them for us, and that he who attains to this most perfectly can be called excellent.[Pg 184] This truth, I say, being recognized by Masaccio, brought it about that by means of continuous study he learnt so much that he can be numbered among the first who cleared away, in a great measure, the hardness, the imperfections, and the difficulties of the art, and that he gave a beginning to beautiful attitudes, movements, liveliness, and vivacity, and to a certain relief truly characteristic and natural; which no painter up to his time had ever done."

Masaccio, or Tommaso di Ser Giovanni di Simone, was according to Vasari a very single-minded artist, "absent-minded and unpredictable" and "caring very little about himself and even less about others". Yet, Vasari doesn't interpret this negatively, going on to note that"he embodied goodness itself". He goes on to praise Masaccio's skills in perspective and originality, however his work was not able to improve and develop: as Vasari writes,
"But although the works of Masaccio have ever been in so great repute, it is nevertheless the opinion—nay, the firm belief—of many, that he would have produced even greater fruits in his art, if death, which tore him from us at the age of twenty-six, had not snatched him away from us so prematurely. But either by reason of envy, or because good things rarely have any long duration, he died in the flower of his youth, and that so suddenly, that there were not wanting people who put it down to poison rather than to any other reason."
These are some of Masaccio's works:

Desco da parto (1427-28).

Baptism of the Neophytes (1426-27).

Raising of the Son of Teophilus and St.Peter Enthroned (1427).

Adoration of the Kings (1425-28).

The Agony in the Garden (1426).

Madonna Casini (1426).

Crucifixion (1426).

Portrait of a Young Woman (1425).

Distribution of Alms and Death of Ananias (1424-25).

St. Juvenal Triptych (1422).

The Trinity (1427-28).

Next time: The Life of Filippo Brunelleschi, Sculptor and Artist.