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We will start off with a journey through Galileo Galilei’s life. Starting from his early life, his scientific career, his struggles with the catholic church (and the two letters), and finally his lifetime sentence.

Then we’ll jump to the year 2018, where Galileo’s long-lost letter was discovered in the Royal Society in London.

Galileo Galilei was born February 15, 1564, in Pisa, Italy. His father was a musician and a scholar, he also contributed to the theory and practice of music. Nonetheless, in Galileo’s preteens he attended a monastery school. During that period, he contemplated becoming a monk. However, his father did not approve and moved him to a different school.

Monastery school at Vallombrosa that Galileo attended

At the age of 16, under the influence of his father, he joined the University of Pisa to study medicine. However, during his time at the university he became infatuated with mathematics. He made the decision to devote his life to mathematical subjects and philosophy. Therefore, against his fathers’ protests, he dropped out of the university.

His love for mathematics was immense, he was quoted saying:

“Philosophy is written in this grand book that is the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and read the letters in which it is composed. It is written in the language of mathematics, and its’ characters are triangles, circles, and other geometric figures. Without which it is humanly impossible to understand a single word of it.”

He began his profession by tutoring mathematics, while doing that he also began conducting experiments, specifically in the field of mechanics. He made several discoveries, some of which contradicted Aristotelian physics (ex. Law of falling objects). This implanted a little doubt in Galileo about Aristotle.

In 1592, Galileo moved to the University of Padua, where he was appointed the chair of mathematics. The University of Padua was intellectually liberal and was beyond the jurisdiction of the Pope.

In 1609, he learnt that a guy in the Netherlands have discovered an object that makes far things seem nearby (spyglass). Which pondered him, and he then attempted to construct an object that would achieve the same purpose. After trial and error, he succussed, as well as improved its’ mechanics and magnification. Hence, Galileo made himself a telescope.

Two of Galileo’s first telescopes

Instead of the original use of the spyglass, Galileo pointed his telescope to the sky, where he started studying the planets. Consequently, he made several observations, which include: 1) the moon is not smooth, but rather a mountainous surface, 2) there are satellites (moons) orbiting Jupiter, 3) Venus and Mercury had phases. The fist observation contradicts Aristotle and the church’s belief that the heavenly objects are pristine. Whereas the second observation shot a hole in the argument that if Earth is to move it would lose its’ moon. Furthermore, the third observation suggests that Venus and Mercury are rotating around the sun (which goes against the geocentric belief at the time). These observations led Galileo to exploring Copernicus’s theories, as well as discussing them.

In 1610, against his friend’s advice and in pursuit of more money, he left the protective environment of Padua and moved to Florence to work as “Chief Mathematician and Philosopher to the Grand Duke”. In 1613, the Grand Duchess (a religious woman) wrote a letter to one of Galileo’s friends, Castelli, inquiring about Galileo’s discoveries and his support for Copernicus. Castelli addressed her questions in addition to informing Galileo about her concerns.

Galileo responded to the situation with two letters; one addressed to Castelli and the second one addressed to the Grand Duchess. In his letter to the Grand Duchess, he elaborated his ideas in a politically correct manner and used a lot of scriptures to convey his message. However, in his letter to Castelli he was not attempting to be politically correct, but rather he argued that “scientific research should be free from theological doctrine”, also “references in the bible to astronomical events should not be taken literally, because scribes have simplified these descriptions so that they can be understood by common people” he additionally said that “religious authorities who argued otherwise, do not have the competence to judge”. He mainly explained to his friend that the heliocentric model is not incompatible with the bible.

During that time letters used to be circled around to spread ideas and knowledge. It was common that copies of letters start emerging and circulating around the community to further study and investigate these ideas. Unfortunately for Galileo, his letter to Castelli caused a storm in the community, and eventually in 1615 the letter found its’ way to a Dominican frier named Lorini.

Lorini forwarded the letter to the inquisition in Rome. Galileo believed that the copy they have was somewhat fabricated, so he asked Castelli to return the original letter. He then asked a friend to send his original letter to the inquisition. So, the inquisition acquired two versions of the letter; the first, which was from Lorini, was inflammatory, and the second, which was from Galileo, was less inflammatory. In 1616, the catholic church banned Copernicus’s book “Six Books Concerning the Revolutions of the Heavenly Orbs”, and the Pope summoned Galileo to Rome, where he warned him about supporting and teaching Copernicus’s ideas.

In 1624, Galileo went to Rome to visit the Pope and had several interviews with him. He finally, described to him some of his arguments about Earth’s motion to obtain his permission to publish his book. The Pope approved of him publishing the book, but under the condition that the Copernican theory would only be addressed hypothetically.

Galileo wrote his book titled “Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican”. The book was finished in 1630, and he added a preface that states that the content of the book is hypothetical. Which gave him little trouble in publishing the book. The idea of the book is a debate between people; Salviati (representing Galileo), Sagredo (the intelligent layman), and Simplicio (the dyed-in-the-wool Aristotelian). In the book Simplicio comes across as a witless man that supports Aristotle, therefore, it was evident that the book was greatly supporting Copernicus’s theory. Galileo even gave Simplicio the final word, which states “God could have made the universe anyway he wanted to, and still made it appear to us the way it does.”, which is ironically the Pope’s favorite argument.

Galileo’s book Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican

The reaction against the book was abrupt. The Pope summoned a special board to examine the book and make recommendations. The board found that he did not treat the Copernican theory hypothetically. Therefore, they summoned him to Rome, where they confronted him with the 1616 order. The 1616 order stated that he should not defend or teach Copernicus’s theory in public. Furthermore, they banned his book and sentenced him to life imprisonment. Galileo took the sympathy route and convinced them, because of his age and health, to house arrest instead.

Galileo was allowed visitors while under house arrest. Students and scholars visited him often to converse and exchange ideas. Against the order of the church, Galileo published a new book. One of the students that used to visit him helped him get it published in the Netherlands. Galileo became blind after finishing the book and died in 1642.

Now, going back to the letters that got him in trouble back in 1616. The original letter that was addressed to Castelli was lost for about 400 years. Until one day in 2018 a postdoctoral science historian, Salvatore Ricciardo, was at the Royal Society in London browsing the online library. To his surprise, he stumbles upon a misdated letter and after reading it, quickly realized that it is the long last letter! The original letter that was sent to Castelli. “I thought, ‘I can’t believe that I have discovered the letter that virtually all Galileo scholars thought to be hopelessly lost,’” says Ricciardo. “It seemed even more incredible because the letter was not in an obscure library, but in the Royal Society library.”

The original letter in which Galileo argued against the doctrine of the Roman church

After scrutinous handwriting analysis, it was confirmed that it was Galileo’s handwriting and that it is his original letter to Castelli. The letter had numerous scribble and edits done by Galileo to tone down the language used. This proved that the version Lorini provided to the Vatican was correct, whereas the one provided by Galileo was edited to appear less inflammatory. Some examples of the edits are:

  • He referred to certain statements in the Bible as “false if one goes by the literal meaning of the words”. He crossed the word “false” and replaced it with “look different from the truth”
  • He changed the word “concealing” when referring to the Scriptures most basic dogmas to the word “veiling”

In summary, Lorini’s letter was true, and Galileo edited the letter to refrain from getting in trouble with the church. So, 400 years later, we finally know the truth about which letter came first.

Check out some other moments

if you enjoyed “The Two Letters” check out our other episode “Comedian” where we talk about contemporary art and some of it’s absurdity