From this time the most important works of Fra Angelico were done in the chapel of Pope Nicholas V., in the Vatican, and in the chapel which he decorated in the Cathedral of Orvieto. He worked there one summer, and the work was continued by Luca Signorelli. The remainder of his life was passed so quietly that little can be told of it. It is not even known with certainty whether he ever returned to Florence, and by some strange fate the key to the chapel which he painted in the Vatican was lost during two centuries, and the pictures could only be seen by entering through a window. Thus it would seem that his last years were passed in the quiet work which he best loved. [Illustration: FIG. 32.--AN ANGEL. _In the Uffizi, Florence. By Fra Angelico._] When his final illness was upon him, the brethren of Santa Maria Sopra Minerva, where he resided, gathered about him, and chanted the _Salve Regina_. He died on the 18th of February, 1455, when sixty-seven years old. His tombstone is in the church of Santa Maria Sopra Minerva, in Rome; on it lies the figure of a Dominican monk in marble. Pope Nicholas V. wrote his epitaph in Latin. The following translation is by Professor Norton: "Not mine be the praise that I was a second Apelles, But that I gave all my gains to thine, O Christ! One work is for the earth, another for heaven. The city, the Flower of Tuscany, bore me--John." In the Convent of San Marco in Florence there are twenty-five pictures by this master; in the Academy of Florence there are about sixty; there are eleven in the chapel of Nicholas V., and still others in the Vatican gallery. The Church of Santa Maria Novella, Florence, the Cathedral of Orvieto, the Church of St. Domenico in Perugia, and that of Cortona, are all rich in his works. Besides these a few exist in some of the principal European galleries; but I love best to see them in San Marco, where he painted them for his brethren, and where they seem most at home. The chief merit of the pictures of Fra Angelico is the sweet and tender expression of the faces of his angels and saints, or any beings who are holy and good; he never succeeded in painting evil and sin in such a way as to terrify one; his gentle nature did not permit him to represent that which it could not comprehend, and the very spirit of purity seems to breathe through every picture.