Trial

After many delays—Galileo was once again seriously ill, and the plague had
returned—Galileo arrived in Rome in February 1633 to defend himself before the
Inquisition. The trial began on April 12. The inquisitors focused their attention
on the injunction Bellarmine had issued to Galileo in 1616. Francesco Niccolini,
the Tuscan ambassador to Rome, explained it this way to his office in Florence:
“The main difficulty consists in this: these gentlemen [the inquisitors] maintain
that in 1616 he [Galileo] was commanded neither to discuss the question of the
earth’s motion nor to converse about it. He says, to the contrary, that these were
not the terms of the injunction, which were that that doctrine was not to be held
or defended. He considers that he has the means of justifying himself since it
does not appear at all from his book that he holds or defends the doctrine . . . or
that he regards it as a settled question.” Galileo offered in evidence a letter from
Bellarmine, which bolstered his claim that the inquisitors’ strict interpretation
of the injunction was not valid.
Historians have argued about the weight of evidence on both sides, and on a
strictly legal basis, concluded that Galileo had the stronger case. (Among other
things, the 1616 injunction had never been signed or witnessed.) But for the
inquisitors, acquittal was not an option. They offered what appeared to be a
reasonable settlement: Galileo would admit wrongdoing, submit a defense, and
receive a light sentence. Galileo agreed and complied. But when the sentence
came on June 22 it was far harsher than anything he had expected: his book was
to be placed on the Index of Prohibited Books, and he was condemned to life
imprisonment.