30th International Colloquium Corpus Vitrearum. Barcelona – Cerdanyola – Girona 4–7 July 2022, Organized by the Catalan Committee of the Corpus Vitrearum, Barcelone, Corpus Vitrearum Catalunya.Two major artists from the southern Netherlands, Pieter Coecke (1502–1550) and Bernard Van Orley (1487–1541) distinguished themselves by their versa- tility and their skills as “entrepreneurs”. Both were personally involved in the creation of works in various techniques including panel painting, tapestry and stained glass. Archives and preserved works document or attest to the activity of these artists in these different fields but, beyond the certified or supposed supply of a scale model ("vidimus") or full-scale drawing ("cartoon"), the exact degree of involvement remains difficult to establish. From selected examples, this paper will show the importance and the limits of a connoisseurship approach in surveying the compartmentalization of artistic techniques and in understanding the complex dynamic of artistic creation in the southern Netherlands during the first half of the 16th century.