Benedetto Castelli

Born Antonio Castelli in Brescia and later known by his religious name Benedetto, he entered the Benedictine order in 1595. He studied under Galileo in Padua and became one of Galileo’s most trusted pupils and supporters.

Castelli taught mathematics at Pisa and later in Rome, where he built a strong reputation as a scholar. He is especially remembered for his work on hydraulics, including Della misura dell’acque correnti, a book often described as a landmark in the early scientific study of running water.

His name also appears in the history of astronomy and religion because Galileo’s famous 1613 letter to Castelli was written to him during growing arguments over Copernican ideas and biblical interpretation. Beyond his own research, he helped shape the next generation of scientists, with figures such as Evangelista Torricelli and Bonaventura Cavalieri linked to his teaching and influence.