The Ouroboros, a symbol of mortality in the form of a worm or snake swallowing its own tail, became associated with zero, or nothingness. This Ouroboros emblem showing an infant reclining on its own skull, published in 1635, illustrates an epigram by the first-century Roman poet and astrologer Marcus Manilius: “We start to die when we are born, and the end depends upon the beginning [Nascentes morimur, finisque ab origine pendet].”