The Anatomy of Galileo’s Anagram

This essay offers a new reading of Galileo’s most celebrated anagram, incorporating both the prehistory of his late-1610 disclosure concerning the moon-like phases of Venus, and the awkward “leftover letters,” o and y, of the eventual cypher. It argues for a sustained analogy between components of the optical instrument, musical instruments, and particular anatomical structures described by Galen and elaborated by early modern anatomists in Padua. It proposes, finally, the cypher as a calculated response to the Neapolitan magus and playwright Giambattista della Porta’s challenge to Galileo’s claims about the telescope itself.