The plot of the play concerns the latter period of the life of Galileo Galilei, the great Italian natural philosopher, who was persecuted by the Roman Catholic Church for his promolugation of his scientific discoveries. The play embraces such themes as the conflict between the dogmatic church and science, as well as constancy in the face of oppression.
Rough outline of the plot
Galileo is short of money. A new student brings a telescope from the Netherlands. Galileo improves it, but then sells it to the Venetian Republic as his own invention.
Galileo uses the telescope to substantiate Copernicus' heliocentric model of our solar system, which is highly incompatible with both popular belief and church doctrine. His daughter's marriage to a well-off young man (who she is genuinely in love with) fails because of Galileo's recalcitrance to distance himself from his unorthodox teachings.
Galileo is brought to the Vatican for questioning. Upon being threatened with torture, he recants his teachings. His students are shocked by his surrender in the face of pressure from the church authorities.
Galileo, old and broken, living under house arrest, is visited by one of his former pupils, Andrea. Galileo gives him a book containing all his scientific discoveries, asking him to smuggle it out of Italy for dissemination abroad. Andrea now believes Galileo's actions were heroic and that he just recanted to fool the ecclesiastical authorities. However, Galileo insists his actions had nothing to do with heroism but were merely the result of self-interest.
Cast: (in order