Richard of St. Victor (d. 1173) wrote two treatises in mystical theology, sometimes called Benjamin Minor and Benjamin Major. But where do those titles come from? It seems the first one has something to do with the twelve patriarchs (of which one was Benjamin), but that doesn't seem sufficient to explain the titles.
Sharpe, A. (1912). Richard of St. Victor. In The Catholic Encyclopedia. New York: Robert Appleton Company.
his mystical theology […] is mainly contained in the two books on mystical contemplation, entitled respectively Benjamin Minor and Benjamin Major […] the titles Benjamin Major and Minor refer to Psalm 67[:28], "Benjamin[…]in mentis excessu" ["Benjamin…in ecstasy of mind"].