1749—France

In the earliest documented use of trombone in a French orchestra, a letter from the Comte de Clermont to the Comte de Billy names the trombone (even using the term “trombone,” not “sackbut”) among 28 instruments in his orchestra (Guion, Trombone 168).

mid-1700s—Germany: Reorganization of military bands gives trombone the role of strengthening bass line. Trio maintained in large infantry bands and in orchestras. Technical changes include realignment of the old high A pitch (of the tenor) to concert and band pitch Bb and acceptance of seven chromatic slide positions instead of the previous diatonic positions.

mid-1700s—Although each nation has its own ideal in terms of the instrument’s bore size, etc., greater terminal flare of the bell is adopted universally (Remnant, Illustrated 151).