MORE INFORMATION 
Many names have been given to the Renaissance trombone, including sackbut (literally "push-pull"), saqueboute, shakbusshes, seykebuds, sakbuds, shakebuttes, shagbutts, and even shagbolts. Detailed information about the instrument is given by Praetorius


https://www.music.iastate.edu/antiqua/files/instrument/files/sacbut.mp3



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