Twelve months are necessary from the first day of the beginning. In thirty days and earth is generated out of lead, or the nature of the earth makes lead grow. In one hundred days argent vive grows in water. In sixty days complete there grew an air out of tin complete. In the other days of the year, fire grows from gold. In the moment of the year ending, the soul, the middle nature, descends from heaven into this earth, and mortifies the superior and inferior powers. The image of a manifold victory to consume the war in the heart of the belly of them, even to the perpetual judgement of fire. I will tell you no more.
Marsilius Ficinus, ‘Liber de Arte Chemica,’ 1518