Michelangelo chose for his subject the Story of the Creation, the Fall of Man, the Flood, and the Second Entry of Sin into the World, illustrated by a series of nine compositions on the central space of the ceiling. Twenty magnificent nude figures, representing Athletes, decorate the corners of these central compositions, and support bronze medallions held in place by oak garlands and draperies. The shape of the ceiling is what is commonly called a barrel vaulting resting on lunettes, six to the length and two to the width of the building. The second part of the decoration demonstrates the need for a scheme of Salvation, promised by the Prophets and Sibyls, whose majestic figures are painted alternately in the triangular spaces between the lunettes, in the lower part of which is a series of wonderful groups representing the ancestors of Christ. Michelangelo, although engaged on a great pictorial work, never considered himself as anything but a sculptor, and followed in painting the same systems that he would have adopted in his own art. Sir Charles Holroyd, in his recent most valuable contribution to Michelangelesque literature, very justly remarks: "When Pope Julius prevented Michelangelo from going on with his beloved project of the tomb and made him paint the vault, the master set to work to produce a similar conception to the tomb in a painted form. The vault became a great temple of painted marble and painted sculptures raised in mid air above the walls of the chapel. The cornices and pilasters are of simple Renaissance architecture, the only ornaments he allowed himself to use being similar to those he would have used as a sculptor. Acorns, the family device of the della Rovere, rams' skulls, and scallop shells, and the one theme of decoration that Michelangelo always delighted in--the human figure. The Prophets and Sibyls took the positions occupied by the principal figures designed for the tomb, like the great statue of Moses. The Athletes at the corner of the ribs of the roof were in place of the bound captives, two of which are now in the Louvre, and the nine histories of the Creation and the Flood fill the panels like the bronze reliefs of the tomb." Michelangelo must have toiled with almost superhuman energy at his great work. In a letter to his favourite brother, Buonarroto, dated October 17th, 1509, he writes: "I live here in great distress and with the greatest fatigue of body, and have not a friend of any sort, and do not want one, and have not even enough time to eat necessary food." This is not surprising when we remember that as early as the 1st of November, 1509, the first and most important part of this colossal work, which comprises three hundred and ninety-four figures, the majority ten feet high, was exposed to view, and greatly admired by the Pope, who, being vehement by nature and impatient of delay, insisted upon having it uncovered, although it was still incomplete.