This Latin carol takes its text from the ancient Piae Cantiones, dating back to 1582, but the associated melody is even older: the Oxford Book of Carols attributes it as 'German, 1360'. It is often used as a processional, especially for services commemorating the Feast of the Holy Innocents, in honour of the young boys slain by King Herod.
Several English translations exist, not literal but metrical paraphrases: most commonly encountered is the anonymous 'Sing aloud on this day'.
Personent hodie
Voces puerulae,
Laudantes jucunde
Qui nobis est natus,
Summo Deo datus,
Et de vir, vir, vir,
Et de vir, vir, vir,
Et de virgineo ventre procreatus.
Immundo nascitur,
Panis involvitur,
Praesepi ponitur
Stabulo brutorum,
Rector supernorum.
Perdidit, dit, dit,
Perdidit, dit, dit,
Perdidit spolia princeps infernorum.
Magi tres venerunt,
Parvulum inquirunt,
Bethlehem adeunt,
Stellulam sequendo,
Ipsum adorando.
Aurum, thus, thus, thus,
Aurum, thus, thus, thus,
Aurum, thus, et myrrham ei offerendo.
Omnes clericuli,
Pariter pueri,
Cantent ut angeli:
Advenisti mundo,
Laudes tibi fundo.
Ideo, o, o,
Ideo, o, o,
Ideo gloria in excelsis Deo!
Everything Hymnal