Galileo famously insisted in the early seventeenth century that the Earth goes round the Sun and not vice versa – an idea that got him into deep trouble with the Catholic Church. In 1633 Galileo was put in trial for heresy by the Inquisition, and was threatened with imprisonment, or worse, if he didn’t recant. Galileo spent the rest of his days under house arrest and is now seen by some as a near-martyr to science in the face of unyielding religious doctrine. But the discovery of a letter questions the received version of events. Philip Ball tells the story of the relationship between Galileo, the church and his fellow professors. Philip talks to science historians Professor Paula Findlen of the University of California and Professor Mary Jane Rubenstein of Wesleyan University about Galileo's time and about the history of the relationship between science and religion.