Portrait painting benefitted greatly from such commissions and from the general appreciation of art by bourgeois clients, who supported portraiture as well as still-life and landscapes painting. In addition, the first significant art and dealer markets flourished in Holland at that time. With plenty of demand, Rembrandt was able to experiment with unconventional composition and technique, such as chiaroscuro. He demonstrated these innovations, pioneered by Italian masters such as Caravaggio, most notably in his famous "Night Watch" (1642). "The Anatomy Lesson of Dr. Tulp" (1632) is another fine example of Rembrandt's mastery of the group painting, in which he bathes the corpse
Nicolaes Tulp but also because of the fantastic stories that he relates. An example; Jan de Doot, a blacksmith in Amsterdam, was in such pain from a bladder stone, that he sharpened a knife and removed it himself, because he refused to be the victim of the 'stone cutters'. These were the barber-surgeons who performed such procedures but had a high death rate. To everyone's surprise, Jan de Doot survived this operation which was said to produce a stone the size of an egg. A painting illustrating this story is in the collection of the Anatomy Museum of Leiden. Tulp minutely described