Orientis partibus is a playful hymn addressed to an ass. It comes from a liturgy for the Feast of the Circumcision, which was later known as the Feast of Fools, from the Church of Sens in France in the 1200s.(MS. 46 of the Bibliothèque Municipale de Sens)It was sung in numerous medieval Christmastide pageants which featured the ass who bore Our Lady to Egypt; however, in this version, an additional stanza makes it clear it is addressed to the ass who bore the magi to Bethlehem. It is presumed that the layfolk sang the refrain, Hez, sir Asne, hez; the only words in the vernacular in this liturgy.

The music can be rhythmically interpreted in 4 or in 3.
Here are the lyrics with an English translation:
1) Orientis partibus adventavit asinus pulcher et fortissimus sarcinis aptissimus Hez, Sir Asne, Hez! In eastern lands the ass arrived pretty and so strong fit for burden Hail, Sir Ass, Hail! 2) Hic in collibus Sychen iam nutritus sub Ruben transiit per Jordanem saliit in Bethlehem Hez, Sir Asne, Hez! Here in the hills of Sychen, already suckled below the Ruben, he crosses the Jordan; he enters Bethlehem. Hail, Sir Ass, Hail! 3) Saltu vincit hinnulos damas et capreolos super dromedarios velox madianeos Hez, Sir Asne, Hez! In his leaps he conquers the mules, the fallow deer and roebucks and surpasses the fast camels of the Medes. Hail, Sir Ass, Hail! 4) Aurum de Arabia, Thus et myrrham de Sabba Tulit in ecclesia Virtus asinaria. Hez, Sir Asne, Hez! Gold from Arabia, Incense and myrrh from Sabba, bore to the church this virtuous ass. Hail, Sir Ass, Hail! 5) Dum trahit vehicula multa cum sarcinula illius mandibula dura terit pabula Hez, Sir Asne, Hez! While he pulls carts, many with heavy loads, his jaws grind tough fodder. Hail, Sir Ass, Hail! 6) Cum aristis, hordeum comedit et carduum triticum ex palea segregat in area Hez, Sir Asne, Hez. He eats barley, beards and all, and spiny thistles. He separates the wheat from the chaff on the threshing floor. Hail, Sir Ass, Hail! 7) Amen dicas, asine Iam satur ex gramine amen, amen itera aspernare vetera Hez, Sir Asne, Hez. You say “amen”, ass, all filled with grass “amen, amen” once again, spurning the past. Hail, Sir Ass, Hail!
Sheet music with both rhythmic interpretations:
This version alternates between the rhythmic interpretations