It was common practice for major artists, such as Isenbrandt, to paint only the major parts of his paintings, such as faces and the flesh parts of his figures. His faces and flesh areas are set apart by brown pigment. The background was then filled in by assistants. The end quality of a work depended largely on the quality of the execution and the competency of the assistants, leading to an uneven quality of his works. These assistants also painted, as this was common practice in those times, many versions of the "Madonna and Child", that were then attributed to Isenbrandt, giving him the reputation of having had an enormous body of work. The exhibition in Bruges of Early Netherlandish painting in 1902 showed therefore a large collection of his works. Unlike many contemporary colleagues, he is only documented with one assistant, Cornelis van Callenberghe, who joined his workshop in 1520.