Pictures of Moses with horns

inquiry

Why do some depictions of Moses show him with ram's horns coming out
of his head?

response

This image derives from a mistranslation of the Hebrew word qaran
(H7160) in Exodus 34:29 (see also Ex 34:30,35) by Jerome in the Latin
Vulgate. The Brown-Driver-Briggs Hebrew Lexicon says that this Hebrew
verb means to:
1) (Qal) send out rays 
2) (Hiphil) display (grow) horns (be fully developed).

Qaran is derived from H7161, which is a noun meaning "horn." Jerome
took the basic meaning of the word and neglected its derived meaning
of "to emit rays." Many times in Hebrew one must assign the meaning of
a word based on its context. In Psalm 69:31 qaran is used to describe
an ox or young bull. There the translation as "horn" is
appropriate. But in Exodus 34:29 qaran is used in conjunction with the
phrase "skin of his face." From the context of following versus the
meaning as "horns" is not supported. The Apostle Paul understood this
to mean "shone" and not "grew horns" as can be seen from II Cor
3:7-13. 

As a result of this some Christian representations of Moses can be
found with ram's horns. Further, some have taken this image and used
it in their synthesis of Christianity with the Egyptian Amun and the
Greek Aries to form mystic cults.