 Also in 1623, Maffeo Barberini, Galileo’s supporter and friend, was elected Pope Urban VIII. Galileo felt empowered to begin work on his Dialogue Concerning the Two Chief World Systems. The “two systems” are the Ptolemaic and Copernican, and the text clearly, though not explicitly, favors the latter. Printing was completed in Florence by February 1632. Shortly afterwards, the Inquisition banned its sale, and Galileo was ordered to Rome for trial. In June 1633, Galileo was convicted of “vehement suspicion of heresy,” and a sentence of imprisonment was immediately commuted to perpetual house arrest. (There is more about these events and their implications in the final section of this  article, Galileo and the Church.)