Hals had a large workshop in Haarlem and many students, though 19th century biographers questioned some of his pupils, since their painting styles were so dissimilar to Hals. In his "De Groote Schouburgh" (1718–21), Arnold Houbraken mentions Philips Wouwerman, Adriaen Brouwer, Pieter Gerritsz van Roestraten, Adriaen van Ostade and Dirck van Delen as students. Vincent Laurensz van der Vinne was also a student, according to his diary with notes left by his son Laurens Vincentsz van der Vinne. Roestraten was not only a student (the Haarlem archives contain a notarised document, which supports this fact), but he also became a son-in-law of Hals when he married his daughter Adriaentje. The Haarlem portrait painter, Johannes Verspronck, one of about 10 competing portraitists in Haarlem at the time, possibly studied for some time with Hals.