May 1, 2025

The Cathedral (Duomo) and Galileo

The cathedral is the greatest masterpiece of Pisa Romanesque architecture.

In the 11th century, Pisa, having participated in the Crusades, engaged in a naval battle against an Islamic fleet off the coast of Palermo, Sicily, and emerged victorious.

To commemorate this victory, the cathedral was built over 50 years using the gold and silver treasures seized from the Muslims.

The columns used in the construction were brought back as war trophies from Greek temples in Palermo.

Inside the cathedral, there are numerous works of high historical and artistic value.

Among them, the most notable is the pulpit of early 14th century, which is considered one of the finest examples of Italian Gothic sculpture.

However, for us, an even more important item is the lamp hanging in front of this pulpit.

It was in 1583, before Galileo’s discovery of the "law of falling bodies," that he, then a medical student at the University of Pisa, observed this lamp.

Having received a rigorous education from his enthusiastic father, Galileo entered medical school at the age of 17.

He stood in front of the pulpit of the Duomo, watching a bronze chandelier (lamp) swaying in the wind.

He noticed that, even as the amplitude of the pendulum’s swing gradually decreased, the time for one complete oscillation remained constant.

He was a medical student, so he confirmed this observation by timing it with his own pulse.

This was the discovery of the "isochronism of the pendulum."

Since then, the chandelier in Pisa’s cathedral has been called the “Lamp of Galileo.”

Today, it is believed that Galileo had actually discovered the pendulum’s principle six years before observing this lamp.

Later, disillusioned by his medical lectures, Galileo dropped out of medical school and pursued mathematics, physics, and astronomy.

He went on to teach these disciplines for many years at the universities of Pisa and Padua.

One of his most historically significant contributions was in the field of astronomy.

①    The existence of moons orbiting Jupiter.

②    The phases of Venus.

③    The presence of sunspots on the Sun.

These three discoveries led Galileo to firmly believe that they were evidence supporting the heliocentric theory (that the Earth orbits the Sun).

It is well known that Galileo was convicted by the Catholic Church for advocating heliocentrism, which contradicted the geocentric theory (that the Sun orbits the Earth).

He was disliked because he understood the essence of Christianity better than the church priests and explained it using scientific terms.

As a result, he was sentenced in a sham trial.

Galileo was sentenced to life imprisonment, but his sentence was immediately commuted to house arrest.

However, he was not allowed to return to his home in Florence and was forced to live under surveillance in a designated residence, forbidden from going outside, until his death.

Naturally, he was stripped of all his titles.

Even after his death, his honor was not restored, and he was not permitted a Christian burial.

The Grand Duke of Tuscany, Galileo’s patron, could not bear to see him buried as a heretic and postponed his funeral until permission from the Pope was granted.

More than 100 years later, in the 18th century, Galileo was finally given a proper burial in the Basilica of Santa Croce in Florence with the Pope’s approval.

Eventually, in 1965, Pope Paul VI mentioned the Galileo trial, which initiated a reevaluation of the case.

Finally, in 1992, Pope John Paul II officially admitted that the trial had been a mistake and issued an apology to Galileo.

This is an event that remains fresh in our memories.

This happened 350 years after Galileo’s death—how moving!