It is to a painter less mystical, but not less visionary, that we come in the work of Paolo Uccello, the great "Battle" (52), of which two variants exist, one in the Louvre, the other, the most beautiful of the three, in the National Gallery. It is, as some have thought, a picture of the Battle of S. Egidio, where Braccio da Montone made Carlo Malatesta and his nephew Galeotto prisoners in 1416. Splendid as it is, something has been lost to us by restoration. Paola Uccello, the friend of Donatello and of Brunellesco, was all his life devoted to the study of perspective. Many marvellous drawings in which he traced that baffling vista, of which he was wont to exclaim when, labouring far into the night, his wife poor soul, would entreat him to take rest and sleep: "Ah, what a delightful thing is this perspective." And then, much beautiful work of his has perished. It was on this art he staked his life. "What have you there that you are shutting up so close?" Donatello said to him one day when he found him alone at work on the Christ and St. Thomas, which he had been commissioned to paint over the door of the church dedicated to that saint in the Mercato Vecchio. "Thou shalt see it some day,--let that suffice thee," Uccello answered. "And it chanced," says Vasari, "that Donato was in the Mercato Vecchio buying fruit one morning when he saw Paolo Uccello, who was uncovering his picture." Saluting him courteously, therefore, his opinion was instantly demanded by Paolo, who was anxiously curious to know what he would say of the work. But when Donato had examined it very minutely, he turned to Paolo and said: "Why, Paolo, thou art uncovering thy picture just at the very time when thou shouldst be shutting it up from the sight of all." These words wounded Paolo so grievously that he would no more leave his house, but shut himself up, devoting himself only the more to the study of perspective, which kept him in poverty and depression to the day of his death. Paolo had been influenced, it is said, by Domenico Veneziano, who in his turn was influenced by the work of Masolino and Masaccio. Nothing is known of the birthplace of this painter, who appears first at Perugia, and was the master of Piero della Francesca. His work is very rare; in Florence there are two heads of saints in the Pitti, and Mr. Berenson speaks of a fresco of the Baptist and St. Francis in S. Croce. Here in the Uffizi, however, we have a Madonna and four Saints (1305) from his hand, formerly in the Church of S. Lucia de' Magnoli in the Via de' Bardi. It is a very splendid work, and certainly his masterpiece; something of Piero della Francesca's later work may perhaps be discerned there, in a certain force and energy, a sort of dry sweetness in the faint colouring that he seems to have loved. The Virgin is enthroned, and in her lap she holds our Lord; on the left stands St. John Baptist and S. Francis, on the right St. Nicholas and S. Lucia.