Just added the below image and caption to the Trombone History Timeline (16th century).

1592/1604—Czech Republic: A page from Graduál český features a decorated border with numerous musicians, including a trombonist. The artwork may be by painter Matouš Radouš, who did some of the volume’s decorations (see detail and full image below; public domain) (sources: Museum of Eastern Bohemia, Hradec Králové; Manuscriptorium; artsandculture.google.com; special thanks to Richard Seda).