Michelangelo Buonarotti’s sculpture of Moses is probably the most famous artistic depiction of the Israelite lawgiver and prophet. It also embodies one of the most famous biblical mistranslations. In Exodus 34, the Torah states of Moses that, after descending from Sinai, “the skin of his face shone [karan].” The similarity between the verb meaning “shine” and the word for “horn” (keren) led to St. Jerome’s Latin Bible, and translations based on it, stating that Moses’ face was “horned.” Hence the two protrusions from the head of Michelangelo’s statue.
But Daniel Lispon suggests that the idea of Moses’ horns actually can be traced to an earlier Jewish tradition, as evidenced by a now-forgotten liturgical poem, or piyyut, for the holiday of Shavuot:
The piyyut was written in ancient Aramaic in the dialect of the Land of Israel, and it incorporated Greek words as well. The language and structure of the piyyut date it to the era of the Byzantine empire before the Muslim conquest, but according to the scholar Joseph Heinemann, it is based on a folk song, handed down orally from much earlier.
The piyyut opens with the words Arkin Hashem sh’maya l’Sinai (“God bent Heaven to Sinai”), later describing God as placing rays of glory on Moses’ head. So far, so good in aligning with the biblical text. But then, towards the end of the piyyut, the angels appear before God and are afraid of Moses, as they claim he might gore or headbutt them.
It may be that this combination of Moses’ physical description (the Hebrew wording being open to interpretation) with his supposed ability to headbutt or gore someone (possibly based on a common, popular understanding which arose during this period), is responsible for creating the image of Moses as actually having horns on his head.
The art scholar Malka Rosenthal showed that Moses appeared with horns in Jewish literary illustrations as well. A number of books published in the German city of Fürth between 1741 and 1750 show the figures of Moses and Aharon on the cover, with Moses holding a staff and tablets while a pair of horns appear on his head.
Read more on The Librarians: https://blog.nli.org.il/en/moses_horns/