This article examines Constitutio Tanta 21 which prohibits all commentary on Justinian's Digest, except for ultra-literal translation from Latin to Greek, or what the Greeks call kata poda. It begins by analyzing the terms and significance of Tanta 21, and it then tries to circumscribe the various factors that might have contributed to the formulation of the prohibition, namely the principles applied to Bible translation, the influence of the Roman legal tradition, and finally, the importance of Latin as the language of the law.