Thanks to Bettina Hoffmann, viola da gamba specialist with Modo Antiquo, for bringing my attention to a 17th century German festival book now available online. I already had one of the images, but was able to get a much better reproduction, and the other, with 3 trombone-cornett pairs, is new to me. I’ve added them all to the 17th century timeline (first half). Below is the entry, along with some additional detail views that there weren’t space for in the timeline. The full views of both plates are above.
I’ve also added the info & images to the Females in Trombone History and How to Hold a Sackbut articles.
1617—Stuttgart, Germany: A festival book with engravings by Esaias von Hulsen, published in 1618, portrays the Stuttgart festivals of 1617 surrounding the christening of Ulrich of Württemberg and the marriage of Ludwig Friedrich of Württemberg to Elisabeth Magdalena of Hesse-Darmstadt. It features two different plates in the procession that include 4 different trombonists, all of them apparently female players (see details below; public domain) (sources: Komma 128, Festkultur online).