The term 'minuet' refers both to a French social dance which was very popular in the 18th century, and to the music used to accompany it. Like many social dances of the time, the minuet was quickly adopted by composers and transformed into a 'artistic' instrumental form. The first minuets were introduced into operas by Jean Baptiste Lully. Later, the dance came to be an almost unavoidable part of suites (particularly the ones written by Johann Sebastian Bach). The simple 8-bar repetition that conformed the minuet was expanded into three sections, with a middle one providing contrast by means of different orchestration and key. It became common practice to score this middle section for a trio: as a result this part of the minuet came to be called trio, even when the orchestration was totally different.
This improved form of minuet eventually became the standard third movements in the four-movement classical symphony scheme, and was the basis for the development of the scherzo form.