File:Kopernikus, Nikolaus - Reußner 1578 Portrait1.jpg
The Basel publisher Piero Pierna sent painter Tobias Stimmer to Como in order to produce sketches of the portraits in Giovio's book.
Stimmer apparently also acquired a portrait of Copernicus, allegedly based on a self-portrait by Copernicus.
Stimmer painted the oldest known portrait of Copernicus on Strasbourg astronomical clock in c. 1571/4. Stimmer's portrait shows Copernicus holding a lily of the valley.
The earliest appearance of a portrait of Copernicus in print is Reusner's Icones, printed in Strasbourg in 1587. Tobias Stimmer was involved in this production, and the portraits are based on his sketches, but Stimmer died in 1584, before the work was completed, and the execution of the actual woodcut is attributed to Christoph Murer.
Andreas Kühne, Stefan Kirschner, Biographia Copernicana: Die Copernicus-Biographien des 16. bis 18. Jahrhunderts (2004), p. 14