In the dark winter evening of Jan 11, 1723, the venerable building of the University of Leiden, Holland, and the houses along the canal where it was situated, were festively illuminated with fairy lamps. Every citizen in the small town knew the reason: Professor Boerhaave had restarted his lectures after a serious illness which had chained him to his bed for four months. Thirty years previously, he had begun his practice as a plain physician. Now he was the most popular professor the university ever had. At this time, Boerhaave, 54 years old, was at the height of his power. Boerhaave was born in the early hours of Dec 31, 1668, at Voorhout, a small village near Leiden, as the son of a minister. His great-grandfather had come to Holland from the southern part of East Flanders (now belonging to France), obviously for religious reasons. He was engaged in wooldressing