Gaudete, Gaudete

Gaudete (latin "rejoice) is a sacred Christmas carol, thought to have been composed in the 16th century. It was published in Piae Cantiones, a collection of Finnish/Swedish sacred songs published in 1582. 

The Latin text is a typical medieval song of praise, which follows the standard pattern for the time – a uniform series of four-line stanzas, each preceded by a two-line refrain.