The Quempas is not a medley in the strictest sense. The custom of singing the Quempas in church at Christmas developed in the 16th century. The three songs Quem pastores laudavere (Whom the shepherds praised highly), Nunc angelorum gloria (Today the dear angels are here), and Resonet in laudibus (Resounding with praise) are woven together into a single song, in which the lines of the songs are sung alternately by different singers at various locations within the church. Today, the Quempas tradition is still maintained in the Ore Mountains, for example, although there are local variations in melody and lyrics.
Unfortunately, the date when the Quempas was first sung is not documented. Its origin likely lies in the 16th century, but possibly also in the 15th century.