Henry Oldenburg was a German theologian, diplomat, and natural philosopher, known as one of the creators of modern scientific peer review. He was one of the foremost intelligencers of 17th-century Europe, with a network of correspondents to rival those of Fabri de Peiresc, Marin Mersenne, and Ismaël Boulliau. At the foundation of the Royal Society in London, he took on the task of foreign correspondence, as the first Secretary.

Ismaël Boulliau was a 17th-century French astronomer and mathematician who was also interested in history, theology, classical studies, and philology. He was an active member of the Republic of Letters, an intellectual community that exchanged ideas. An early defender of the ideas of Copernicus, Kepler and Galileo, Ismael Bullialdus has been called "the most noted astronomer of his generation". One of his books is Astronomia Philolaica (1645).