In around 1485 or 1486, Florentine artist Sandro Botticelli came up with probably his most famous painting, the "Birth of Venus." Botticelli’s choice of subject was nothing new. Venus and her equivalents, including the Greek Aphrodite and the Mesopotamian goddess Ishtar, are among the most common figures depicted in art. Archaeologists dub one of the oldest of all sculptures, the “Venus of Willendorf,” on the assumption that this 25,000-year-old work was intended to represent a Stone Age fertility goddess similar to the Venus of later tradition. In virtually all civilizations, a Venus equivalent plays a prominent role in myth, legend...