Infrared reflectography was used to detect underdrawing beneath the paint. While the artist of this portrait remains unknown, the underdrawing could provide a clue to the authorship, technique and painting process. In several places the underdrawing diverges significantly from the final painting, for example two garters which were originally intended at the knees and were then completed in the paint layers were ultimately suppressed by the artist. Perhaps it was felt that the left one would have diminished the impact of the large tassel hanging from the dagger, which has been given great prominence. Alternatively, the removal of the garters may represent a change in fashion.