I just added this painting and caption to the Trombone History Timeline (19th century, 2nd half). The use of plainchant, played on buccins and trombones, in the late 19th century, is all noteworthy. The painting is also striking in its use of detail, color, and humor.

1886—Spain: Ricardo Villegas Cordero paints After the Mass. The painting features children playing a buccin and a standard trombone, as well as another child picking up a buccin (see below image; public domain).