This statue of Moses, housed at San Pietro in Vincoli (Basilica of St. Peter in Chains), is part of the tomb of Pope Julius II, who was notable for commissioning the Sistine Chapel, as well as the destruction and reconstruction of St. Peter’s Basilica.
This bizarre addition stems from an oddity in Scripture. Here’s the relevant passage, Exodus 34: 29–30, in the New Revised Standard Version (NRSV):
29 Moses came down from Mount Sinai. As he came down from the mountain with the two tablets of the covenant in his hand, Moses did not know that the skin of his face shone because he had been talking with God. 30 When Aaron and all the Israelites saw Moses, the skin of his face was shining, and they were afraid to come near him.
The original Hebrew uses the word qaran or keren here. It can refer to a horn (like a goat’s) or a ray of light. You know, because a light beam can be kind of horn-shaped, I guess. The first translation is more common by far.
For reasons that are not entirely clear, the Greek translation of Scripture, called the Septuagint, translates this phrase as “his face was glorified.”
Later on, one of my favorite saints, Jerome, produced the Vulgate, which was the first comprehensive translation of Scripture into Latin. Jerome translated qaran as cornuta. The root of this Latin word, cornus, can mean a horn (like a trumpet) or a horn (like a goat’s). This is where we get the English words cornet, cornucopia, and, yes, unicorn.
Ancient religions interpreted horns as a sign of power, strength, and sanctity. Indicating that Moses was suddenly “horned” upon his descent from Sinai would have been a clear indication to the local audience that he’d had a close encounter with the divine atop the mountain. Given all this, we can understand the choice of “glorified” in the Septuagint.
So, did Moses actually sprout horns? We shouldn’t rule out that possibility. Crazier things had happened to Moses, after all. Fr. John Echert has suggested the same.
In his execution of the scene, Michelangelo himself seems to be unsure of what to do. After all, those horns are pretty weird-looking. Are we to believe that history’s greatest sculptor couldn’t pull off a regular set of horns? Was he trying to avoid equating Moses with a beast or, even worse, a demon? Nobody knows. Taylor Marshall even goes so far as to suggest that they are designed to look like the two tablets of the Decalogue, emerging from Moses’ mind. With respect to Dr. Marshall, I think this is a stretch — but it goes to illustrate the depths of confusion about this topic that remain even today.