The valve trombone enjoyed its greatest popularity in the 19th century when the technology of rotary valve and piston valve instruments was developing rapidly. By the end of the 19th century, mass production of reliable, higher quality slide trombones led to a return of its popularity. Despite the continuing popularity of the slide trombone, valve trombones have remained popular in, for example, Austria, Italy, Bohemia, Moravia, Slovakia, Spain, Portugal, South America and India, almost to the exclusion of the slide trombone.