Onagers in the Roman Legions

[Koyuncu]

If I remember correctly, in the series of BBC's Building the Impossible : Roman War Machine, team build up scorpio used in famous siege of Masada. According to sources available about siege Romans built that machine in ten days but it is unclear if they are just brought together prefabricated parts or built if from scratch. In the documentary, Alan Wilkins another Roman artillery expert advise team about specifics.

Maybe this was the habit of Romans to build such machinery on field yet it seems this matter needs more information to be sure.