I just added the below image and caption to the Trombone History Timeline (15th century).
c. 1465—France: An anonymous illustration in Pierre Michault’s La Dance aux aveugles includes what may be a trombone. A related passage from the manuscript says, “From her [Fortune’s] manner she seemed really to be unsettled, or at least unsteady, and also her eyes were blindfolded like the god Cupid. In her right hand she had a royal scepter, and at her left was a wheel, turning continually. On a tall pillar next to her throne there was a man very richly dressed, who had in his hand a silver trumpet [trompete d’argent], which he sounded frequently. And at the foot of the throne there was another man, miserably dressed, who had also a trompette, but this one was made of wood and in a very old style, and it had already seen such long service that it was all used up and broken, though it had been repaired in many places with small cords. With the sound of their trompes these minstrels assembled [the dancers] and had them dance in the presence of their Lady, like many people I have seen in Cupid’s gardens.” The artist of the related illustration may have confused the two instruments described in the manuscript, particularly in light of which one appears to be metal and which is wood (see detail and full image below; public domain).