Jan Mostaert was closely linked with the early Haarlem school of painting and the tradition of Geertgen tot Sint Jans. According to van Mander, one of Jan's descendants was a painter and the father of the twin painters Gillis Mostaert and Frans Mostaert (c. 1528/9–1560). Although born in Hulst, in the northern Netherlands, van Mander claimed that both Gillis and Frans trained in Antwerp, Gillis with Jan Mandijn, Frans with Herri met de Bles. This would explain both Gillis's attachment to the tradition of Hieronymus Bosch and Frans's specialization in landscape painting.