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).

Johannes Kepler was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of planetary motion, and his books Astronomia nova, Harmonice Mundi, and Epitome Astronomiae Copernicanae, influencing among others Isaac Newton, providing one of the foundations for his theory of universal gravitation. The variety and impact of his work made Kepler one of the founders and fathers of modern astronomy, the scientific method, natural and modern science. He has been described as the "father of science fiction" for his novel Somnium.