On the pendentives between the spaces of the windows, running up to the ends of each of the five lesser pictures, Michelangelo placed alternate prophets and sibyls upon firm projecting consoles. Five sibyls and five prophets run along the side-walls of the chapel. The end-walls sustain each of them a prophet. These twelve figures are introduced as heralds and pioneers of Christ the Saviour, whose presence on the earth is demanded by the fall of man and the renewal of sin after the Deluge. In the lunettes above the windows and the arched recesses or spandrels over them are depicted scenes setting forth the genealogy of Christ and of His Mother. At each of the four corner-spandrels of the ceiling, Michelangelo painted, in spaces of a very peculiar shape and on a surface of embarrassing inequality, one magnificent subject symbolical of man's redemption. The first is the raising of the Brazen Serpent in the wilderness; the second, the punishment of Haman; the third, the victory of David over Goliath; the fourth, Judith with the head of Holofernes. Thus, with a profound knowledge of the Bible, and with an intense feeling for religious symbolism, Michelangelo unrolled the history of the creation of the world and man, the entrance of sin into the human heart, the punishment of sin by water, and the reappearance of sin in Noah's family. Having done this, he intimated, by means of four special mercies granted to the Jewish people--types and symbols of God's indulgence--that a Saviour would arise to redeem the erring human race. In confirmation of this promise, he called twelve potent witnesses, seven of the Hebrew prophets and five of the Pagan sibyls. He made appeal to history, and set around the thrones on which these witnesses are seated scenes detached from the actual lives of our Lord's human ancestors.