Later in his life, Jacob Cornelisz van Oostsanen ran a workshop with pupils, like his son Dirk Jacobsz and Jan van Scorel did after him. In the workshop, his assistants helped him design book illustrations, woodcuts and stained-glass windows. After 1526 Jacob produced only one known painting, "Self Portrait" (1533). Scholars were led to believe this was the year of his death, but according to Dutch historian I. H van Eeghen there was a seven-year gap between paintings, which was unusual. She suggested it could have been his son that produced the "Self Portrait" (1533).