Many of the entries from the Alto in Treatises page had not yet been included in the Alto Trombone Timeline, so those were added to the timeline. They include many primary sources relevant to alto trombone history, including those by Seyfried/Albrechtsberger, Prout, Barrett, Claus, Schroeder, Vincent, Elson, Ergo, Clappé, Forsyth, Gilson, and White.
Update to Alto in Treatises Page

Made the below update about Seyfried’s edition of Albrechtsberger’s treatise to the Alto in Treatises page. This is a significant piece of the puzzle in the history of the alto trombone because 1) the original Albrechtsberger treatise does not provide enough information to definitively distinguish the key of the alto trombone, particularly if you acknowledge [...]
Alto in Treatises

Trombone History: Added a new page, Alto in Treatises, that gives quotations from more than 45 treatises, dictionaries, and methods, most of them primary sources. It is arranged chronologically and spans from 1600 through the first quarter of the 20th century, offering a compelling view of the role of the alto trombone in trombone history. [...]