Galileo was ordered to turn himself in to the Holy Office to begin trial for holding the belief that the Earth revolves around the sun, which was deemed heretical by the Catholic Church. Standard practice demanded that the accused be imprisoned and secluded during the trial.
For historical context, Galileo Galilei believed that the world circled around the sun, rather then the sun circling the world (as the Roman Catholic Church suggests). The Roman Catholic Church persecuted Galileo and tried to silence him due to his discovery that was contradictory to the teachings of the Roman Catholic Church, in which it, when proven true, would lead people to question other teachings of the Catholic Church and "lead people astray". Therefore, in an effort to not only keep the public image of the Catholic Church afloat, but also the respect and therefore funding of the church, The Roman Catholic Church moved to punish Galileo.
