Galileo, born in Pisa in 1544, is considered together with Keplero, Descartes, Bacon, one of the founding fathers of modern science. Following the Copernican thesis, Galileo rejects the anthropocentric system and establishes a new physical-mathematical science based on the experimental method.
The Dialogue concerning the two chief world systems, a work with popular intent, is written in Vernacular instead of Latin because Galileo is speaking not to the academics, staunch traditionalists, but to the new intellectual class interested in the progress of science.
The dialogue is between three interlocutors: Simplicius, who represents the traditional and dogmatic doctrine; Filippo Salviati, the copernican scientist, and Francesco Sagredo, the free spirit, a learned and experienced man.
The work discusses and denies the foundations of aristothelic physics, and the fake reasonings of Aristotle who thought the earth was the immovable centre of the world with the constellations and the sun revolving around it.
A few months after publication, the Dialogue is confiscated by order of the Inquisition. Galileo is tried and convicted by the Holy Office for his heretical thesis. On his knees, he pronounces the abjuration in which he denies all the theories he had advocated until then.

Abjuration pronounced by Galileo

I, Galileo, son of the late Vincenzo Galilei of Florence, being 70 years old, and kneeling before you most Eminent and Reverend Cardinals, general Inquisitors against the heretic depravity in all the Christian Republic; having the sacred Gospels before my eyes, and touching them with my very hands, swear that I have always believed, believe now and, with God's help, will in the future believe all that the Holy Catholic and Apostolic Church doth hold, preach and teach. But since, after having been admonished by this Holy Office entirely to abandon the false opinion that the sun is the centre of the Universe and immovable, and that the Earth is not the centre of the same and that it moves, and that I was neither to hold, defend, nor teach in any manner whatsoever, either orally or in writing, the said false doctrine; and after having received a notification that the said doctrine is contrary to Holy Writ, I wrote and published a book in which I treat this condemned doctrine and bring forward very persuasive arguments in its favour without answering them: I have been judged vehemently suspected of heresy, that is of having held and believed that the Sun is at the centre of the Universe and immovable, and that the Earth is not at the centre and that it moves. Therefore, wishing to remove from the minds of your Eminences and all faithful Christians this vehement suspicion reasonably conceived against me, I abjure with a sincere heart and unfeigned faith these errors and heresies, and I curse and detest them as well as any other error, heresy or sect contrary to the Holy Catholic Church. And I swear that for the future I shall neither say nor assert orally or in writing such things as may bring upon me similar suspicions; and if I know any heretic, or one suspected of heresy, I will denounce him to this Holy Office, or to the Inquisitor or Ordinary of the place in which I may be.