The Fugue became central to the composition in the baroque music. Being able to compose such pieces displayed the expertise of composers. During this period there was also a increase in music theory, which allowed the musicians to design fugues to teach contrapuntal technique to students.
A fugue usually has three sections: an exposition, a development, and a recapitulation containing the return of the subject in the fugue's tonic key, which is a three note tone. Jan Pieterszoon Sweelinck, Girolamo Frescobaldi, Johann Jakob Froberger and Dieterich Buxtehude all wrote fugues, and George Frideric Handel included them in many of his oratorios. The fugue impacted the baroque music that when the baroque musical movement ended, the form followed into the classical era.
Johann Sebastian Bach used this musical form in the famous Concerto for Two Violins in D Minor (although which has a fugal opening section to its first movement.