In this edition of 'Phoebus Focus', no less than three specialists examine two of the sketches that Baroque master Abraham Van Diepenbeeck made for the stained-glass windows of the Antwerp St. Paul's Church. The stained-glass windows themselves have not survived the ravages of time and so these sketches are invaluable for the reconstruction of the church's original interior.Madeleine Manderyck (1952) studied antiquity and art history at the University of Leuven and took a postgraduate course in heritage preservation at the Hoger Architectuur Instituut van het Rijk in Antwerp. Since 1976, she has worked for the Flanders Heritage Agency of the Flemish government. She was responsible for cases related to historical interiors, with a specialization in stained glass window art. She is the chairwoman of the Flemish and Belgian committee of Corpus Vitrearum. This is an international research project under the auspices of the Union Académique Internationale with the aim of studying monumental stained glass windows worldwide.Jan Van Damme is an art historian and a member of the Corpus Vitrearum Medii Aevi, which is dedicated to the study of stained glass window art.Zsuzsanna van Ruyven-Zeman (1953) studied art history at the Vrije Universiteit Amsterdam. In 1990 she obtained a doctorate for her thesis on the painterdesigner Lambert van Noort (c.1520-1570/1571). She specialized in Dutch art of the sixteenth and seventeenth centuries, and has published articles and exhibition contributions on many aspects of it, with an emphasis on stained glass window art and drawings. She is the author of the volumes of Corpus Vitrearum on the stained glass windows in Gouda and in the Netherlands before 1795, and of the ten-volume catalogue of the prints of the Wierix family in the Hollstein series. She is an independent researcher.