Sistine Chapel ceiling of the Sistine Chapel. At the outset, the plaster, "intonaco", began to grow mold because it was too wet. Michelangelo had to remove it and start again. He then tried a new formula created by one of his assistants, Jacopo l'Indaco, which resisted mold and entered the Italian building tradition. Because he was painting "fresco", the plaster was laid in a new section every day, called a "giornata". At the beginning of each session, the edges would be scraped away and a new area laid down. The edges between "giornate" remain slightly visible; thus, they give a good idea of
Primavera (painting) Three Graces of the "Primavera". (Kenneth Clark) The origin of the painting is unclear. Botticelli was away in Rome for many months in 1481/82, painting in the Sistine Chapel, and suggested dates are in recent years mostly later than this, but still sometimes before. Thinking has been somewhat changed by the publication in 1975 of an inventory from 1499 of the collection of Lorenzo di Pierfrancesco de' Medici. The 1499 inventory records it hanging in the city palace of Lorenzo di Pierfrancesco de' Medici and his brother Giovanni "Il Popolano". They were the cousins of Lorenzo de' Medici ("Lorenzo il