Bonaventura Cavalieri, born in Milan in 1598, bridged the divide between classical geometry and the emerging field of infinitesimal calculus. As a mathematician and member of the Jesuates, he spent his career navigating academic appointments and religious commitments in Italy, eventually securing a influential position at the University of Bologna where he finalized his foundational geometric theories.
Ecclesiastical Life and Academic Ambitions
Entering the Jesuates order at age fifteen, he adopted the name Bonaventura and took full vows in 1615. His early academic training at the University of Pisa brought him into contact with Benedetto Castelli and subsequently Galileo Galilei. Despite his scholarly output, he faced years of rejection when applying for mathematics chairs at various institutions, including Sapienza University and the University of Parma. His appointment as Chair of Mathematics at the University of Bologna in 1629 was facilitated by Galileo's support.
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His most significant contribution to mathematics, the method of indivisibles, was conceived as early as 1627 while he was in Parma. This approach, later detailed in Geometria Indivisibilibus Continuorum Nova Quadam Ratione Promota, provided a conceptual precursor to integral calculus. While the publication of this work in 1635 met with mixed critical reception, it influenced subsequent mathematicians, including Evangelista Torricelli and Vincenzo Viviani, who helped refine the theory.
Optics and Astronomy
Beyond pure geometry, his scientific focus included optics and astronomy, detailed in his 1632 publication, Lo Specchio Ustorio. This work examined the properties of conic sections and reflective mirrors, theoretically exploring designs for reflecting telescopes and addressing questions regarding light reflection and parabolic mirrors. Throughout his tenure at Bologna, he promoted the use of logarithms in Italy and produced various texts on physics and planetary motion, including the Treaty on the perpetual planetary wheel.
Final Years and Legacy
Chronic health issues, specifically gout and arthritis, severely limited his mobility and ability to write during his later years. During this period, he relied on his student Stephano degli Angeli to dictate his correspondence and finalize manuscripts. His final major work, Exercitationes Geometricae Sex, was published in 1647, the same year he died in Bologna. His work remains a distinct study in the evolution of geometric thought during the 17th century.
Fast facts
- Born: 1598, Milan
- Died: 1647, Bologna
- Citizenship: Duchy of Milan
- Occupations: Astronomer, mathematician, theologian
- Notable work: Cavalieri's principle
- Employer: University of Bologna (1629-1646)
- Religion: Catholicism
- Languages: Latin, Italian
Questions readers ask
What is Cavalieri's principle?
It is a geometric concept he developed that partially anticipated integral calculus, involving the comparison of areas or volumes based on their cross-sections.
Did Cavalieri belong to the Jesuit order?
No, he was a member of the Jesuates order, which was distinct from the Jesuits.
Achievements
- Notable work: Cavalieri's principle
- Notable work: Directorium Generale Uranometricum
- Notable work: Exercitationes Geometricae Sex
- Notable work: Geometria Indivisibilibus Continuorum Nova Quadam Ratione Promota
- Held posts at University of Bologna
- Educated at University of Pisa
- Fields of research: astrology, mathematics and physics


