When I write, it is based on what I am hearing. I haven't looked it up at the library. I look things up in wikipedia which reports that Monteverdi orchestrated for sackbuts in L'Orfeo. The lecturer at Glimmerglass said this, too. Then I note that a sackbut is an ancestor to the trombone and that Monteverdi would have called it a trombone. Huh? No Sackbuts are listed for the Glimmerglass orchestra, so I am assuming they used trombones.
I heard more brass in the mix in London. When I looked down in the pit at Glimmerglass, I saw a bassoon, a harp, a couple of trombones, two harpsichords, strings and four theorboes. Theorboes are everywhere these days. They are bass lutes, and according to wikipedia they were new with the invention of opera. How interesting. Monody--basically the opposite of polyphony, the thing invented by the camerata--required an increased emphasis on the bass.
It all sounded very sweet.