I just added the below image and caption to the Trombone History Timeline (16th century). I will also be plotting it on the map of Trombone Art in European Churches.
c. 1600—Venice, Italy: Two trombones are included in trophies (decorative clusters) of instruments above the organ pipes at the church of San Giorgio Maggiore. The trombone on the right appears to have lost its bell (see below image; public domain) (see also Wilson 246, where he dates it as c. 1730).
NATHANIEL WOOD
To me, these look like they’re probably mock-ups, especially considering that the bell-to-slide proportion of the left one doesn’t quite seem to work, and the bell stay isn’t quite in the right place. There are similar “dummy” trombones in Freiberg (Saxony) (instruments by Markus Raquet based on the dummies were used on the recording “Wenn Engel musizieren – Instrumente im Freiberger Dom 1594” by Musicy Freybergensis) and in Lüneburg.
wkimball
Thanks for your comment! My wording may have been misleading, but I definitely agree with you that they are not likely to be literal “playable” trombones. You can see a good reproduction of the Peter Spring high altar in Freibourg’s Augustin Church, the first example you refer to, right here (1592-1601). You can also find a nice detail here (1714) of the other example you mention–Lüneburg. There are actually quite a few similar examples, if you look around the Timeline (see especially organ decorations).