Ismaël Bullialdus

Ismaël Boulliau, known in Latin as Ismaël Bullialdus, lived from 1605 to 1694 and was a 17th-century French astronomer, mathematician and Catholic priest who also took an interest in history, theology, classical studies and philology. Born to Calvinist parents, he converted to Roman Catholicism at the age of 21 and was ordained a priest at 26, moving to Paris in 1632, where he worked for some thirty years as a librarian with the Dupuy brothers. He was an active member of the Republic of Letters and an early defender of the ideas of Copernicus, Kepler and Galileo. His books include De Natura Lucis of 1638 and Astronomia Philolaica of 1645, and the physicist Steven Weinberg credited him with making in 1640 the first suggestion of an inverse-square law. He was elected a foreign associate of the Royal Society of London in 1667 and died at the age of 89 at the Abbey of St. Victor in Paris.