Alinari/Art Resource, NY

God creates not only the world but also the astrological calendar, in this 14th-century fresco from the baptistery of the Cathedral of Padua by artist Giusto de Menabuoi. In the accompanying article, Jack M. Sasson notes that God’s first task was to create light, in contrast to pre-existing darkness. “And there was evening and there was morning, one day,” Genesis 1:5 records. Thus, God initiates time itself, and gives us the unit, the day (and, on day seven, the week), with which to calibrate it. In this way, the biblical authors cleverly stifle any questions about what existed before God: Nothing could, for there was no time, no history, before God.

In this fresco, the Earth is surrounded by rings of water, blue air and red fire. The white ring represents the moon, with the subsequent rings showing the order of the planets (according to Ptolemy’s system): Mercury, Venus, the sun, Mars, Jupiter and Saturn, followed by the outermost ring of the fixed stars of the zodiac. The sun (appearing at 10 o’clock in the red ring) is aligned with the sign of Aries, following one traditional view (reflected in the writings of Virgil and Dante) that God created the world in March, at the spring equinox.