Rasmus Bartholin

Rasmus Bartholin, also known by the Latinized name Erasmus Bartholinus, lived from 1625 to 1698 and was a Danish physician and grammarian. Born in Roskilde, the son of Caspar Bartholin the Elder and younger brother of Thomas Bartholin, he travelled in Europe for ten years, staying in the Netherlands, England, France and Italy. He took a Master's degree at the University of Copenhagen in 1647 and a doctorate at the University of Padua in 1654. He was a professor at Copenhagen, first in geometry and later in medicine, and also served as dean of the faculty of medicine, librarian and rector. He wrote the first grammar of the Danish language, De studio lingvae danicae, in 1657. He is remembered especially for his 1669 discovery of the double refraction of a light ray by Iceland spar, which he described accurately although he could not explain it, since the physical nature of light was then poorly understood.