During the 15th century a number of technical improvements were made to the kettledrum, including a change in the way the vellums were tensioned, the old method of bracing or nailing being gradually replaced by skins lapped on by a hoop. At the beginning of the 16th century kettledrums in German-speaking countries began to be equipped with screws to tension the vellum, which was stretched over a hoop.
The term timpani and the French word timbales are derived from the Greek word tympanon (Latin: tympanum) which referred to a drum with a skin.