Galileo Publishes Dialogue on the Two Chief World Systems

February 1632

Galileo printed in Florence a lively Italian dialogue staging a debate between a Copernican and a Ptolemaic, with a slow-witted Aristotelian named Simplicio voicing the pope's own views. The book was a bestseller and a scandal. Within months, the sixty-eight-year-old astronomer was summoned to Rome to answer for a provocation the Vatican could neither forgive nor safely ignore.