Illustration showing Robert Fludd's "insfiat luxins" creation theory. English physician, astrologer, and mystic Robert Fludd (1574-1637) based his theory on the Latin phrase fiat lux (let there be light), found in the Genesis book of the Judeo-Christian bible. A holy bird flies in a circle from the word insfiatins, and when the circle is completed, light will shine forth. This artwork appears in Fludd's philosophical treatise Utriusque cosmi historia (1617).