Franciscus dele Bo Sylvius, the first physician in the Netherlands to defend that the blood circulated in the vessels, was a descendent from an aristocratic protestant family (Calvinist) originally from Flanders with a successful business tradition. His grandfather immigrated to Germany because of religious persecution. Franciscus was born in Hanau, Germany, but spent most of his life in the Netherlands, where he received his education. He attended Medical School at the University of Leiden from 1633 to 1635, but finished in Basel, Switzerland, in 1637. After obtaining his M.D., he practiced medicine for a year and a half in Hanau, but decided to return to Leiden to work as an unpaid lecturer of anatomy at the University of Leiden, while hoping for a paid academic position.

Sylvius had a special interest in brain anatomy, and his studies led to the discovery of the lateral cerebral fissure (cleft), also known as...