Galileo Galilei, the famous astronomer, had three children (Virginia, Livia, and Vincenzo) with his domestic partner Marina Gamba. Because they never married, the children were considered “illegitimate” under Roman Catholic law.

Due to their illegitimate status, marrying off his daughters with respectable dowries was exceedingly difficult in 17th-century Italian society. Consequently, Galileo arranged for both daughters to enter the San Matteo convent in Arcetri near Florence, where they became nuns (Sister Maria Celeste and Sister Arcangela).

More about Galileo

Galileo Was Also an Accomplished Musician

His father, Vincenzo Galilei, was a famous music theorist, composer, and lutenist who taught Galileo to play. Galileo’s younger brother, Michelagnolo Galilei, became a renowned professional lutenist and composer. (Interestingly, Galileo’s own son, Vincenzo, also played the lute!)

He Wanted to Become a Catholic Priest

As a young man, Galileo seriously considered joining the priesthood, but his father encouraged him to enroll in medical school at the University of Pisa instead. Galileo lost interest in medicine and shifted his focus to mathematics and natural philosophy.

1. He Didn’t Invent the Telescope, but He Transformed It

Dutch eyeglass makers invented the telescope in 1608. When Galileo heard of the device, he built his own without ever seeing the Dutch design, improving its magnification from 3x to 30x and turning it toward the night sky.

2. He Named Jupiter’s Moons as a Career Move

In 1610, Galileo discovered Jupiter’s four largest moons. Seeking financial patronage, he named them the “Medicean Stars” in honor of his former student, Cosimo II de’ Medici, who then hired him as official mathematician to the Medici family.

3. He Accidentally Observed Neptune 230 Years Early

While tracking Jupiter’s moons in late 1612 and early 1613, Galileo recorded a faint, dark dot next to the planet. Modern calculations show this was Neptune, though Galileo mistook it for a dim star.

4. The Famous Leaning Tower of Pisa Drop Probably Never Happened

The popular story of Galileo dropping cannonballs off the Leaning Tower of Pisa to test gravity is widely considered a legend written by his secretary decades later. Galileo actually proved his theory by rolling balls down inclined ramps.

5. He Was a University Dropout

Galileo’s father sent him to study medicine at the University of Pisa, but he became obsessed with mathematics instead. He dropped out in 1585 without a degree, yet his brilliance was so apparent that the university hired him four years later as Chair of Mathematics.

6. He Was a Master Inventor Beyond Astronomy

Beyond telescopes, Galileo invented a thermoscope (a precursor to the thermometer), a hydrostatic balance for measuring density, and a military proportional compass for calculating artillery trajectories.

7. He Tried to Measure the Speed of Light

Galileo suspected light was not instantaneous. He designed an experiment using covered lanterns on distant hilltops at night to measure light’s speed, though the speed of light was far too fast for human reaction times to detect.

8. His Middle Finger Is on Display in a Museum

Nearly a century after his death, admirers moving his body to a grand tomb removed several bones. Today, three of his fingers, a tooth, and a vertebra are preserved, with his middle finger on display at the Museo Galileo in Florence.