Restoration of the Sistine Chapel frescoes smoke and exhaust fumes of the city, being "much dirtier than the ceiling proper". The building was a little unstable and had already shifted considerably prior to Michelangelo's work of 1508, causing cracking of the ceiling, the crack in the "Judith" pendentive being so large that it had to be filled with bricks and mortar before painting. The upper part of the ceiling provided Michelangelo an irregular surface due to cracks and water seepage. Continued ingress of water from the roof and from unroofed exterior walkways above the ceiling level had caused seepage which carried down salts from the building
The Birth of Venus Politian speaks of Zephyr causing flowers to bloom, and spreading their scent over the land, which probably explains the roses he blows along with him in the painting. Having a large standing female nude as the central focus was unprecedented in post-classical Western painting, and certainly drew on the classical sculptures which were coming to light in this period, especially in Rome, where Botticelli had spent 1481–82 working on the walls of the Sistine Chapel. The pose of Botticelli's "Venus" follows the Venus Pudica ("Venus of Modesty") type from classical antiquity, where the hands are held to cover the breasts