Johann Pachelbel's Canon in D is a cornerstone of Baroque chamber music. Interestingly, despite its immense popularity today, it was relatively obscure for over 200 years after its composition until it was rediscovered and popularized in the 20th century. It is not a canon in the strictest sense for its entire duration but begins with a famous canon over a ground bass (a repeating bass line), a technique Pachelbel mastered. Its harmonic progression has become one of the most used and recognized in modern pop music.