NMM 9966. Tristan trumpet by Gebrüder Alexander, Mainz, ca. 1925. Made of ebony with an internal brass tube and one Périnet valve, which lowers the pitch a whole tone. Tristan trumpets were first built to fulfill Richard Wagner's desire to have a wooden trumpet, similar in sound to a Swiss Alphorn, to play the happy melody that announces the arrival of Isolde in the third act of his opera, Tristan und Isolde, which premiered in Munich in 1865. Joe R. and Joella F. Utley Collection, 2001.

Tristan trumpets were always built as a special order. This example, which retains its original case, was built for the National Opera in Prague. However, after World War II, when Wagner's music lost its popularity, it was given to a staff member who owned it for more than forty years. Subsequently, it was sold to a German collector. The bell is stamped: MAJETEK ZEMSKÝ [state owned] / Majetek Národní divadla / v Praze R - 012 [property National Theater in Prague].

Plaque nailed into original case is embossed:
GEBR  ^.  ALEXANDER / MAINZ.