Francesco Grimaldi was an Italian physicist and Jesuit priest who is best known as the first person to describe the diffraction of light. Apart from his optical research, Grimaldi also conducted experiments on human physiology and made careful observations of the surface of the Moon.

Grimaldi was born in Bologna, Italy, in 1618. While his family was fairly wealthy, his father died when Francesco was rather young; his mother tended the family business while he and his brother entered the Society of Jesuits in 1632. For thirteen years Grimaldi studied theology and philosophy and, in 1645, was finally awarded his degree. He required just two more years to obtain his doctorate, at which time he was appointed to a professorship at the Jesuit College in Bologna in the philosophy department. Grimaldi's health began to decline, however, and within a year he was appointed to a less stressful position, that of professor...