1265–1273 · Thomas Aquinas, Summa Theologica II-II, q. 36, a. 4, ad 3
Reply to Objection 3: The number of envy's daughters may be understood for the reason that in the struggle aroused by envy there is something by way of beginning, something by way of middle, and something by way of term. The beginning is that a man strives to lower another's reputation, and this either secretly, and then we have "tale-bearing," or openly, and then we have "detraction." The middle consists in the fact that when a man aims at defaming another, he is either able to do so, and then we have "joy at another's misfortune," or he is unable, and then we have "grief at another's prosperity." The term is hatred itself, because just as good which delights causes love, so does sorrow cause hatred, as stated above (Q[34], A[6]). Grief at another's prosperity is in one way the very same as envy, when, to wit, a man grieves over another's prosperity, in so far as it gives the latter a good name, but in another way it is a daughter of envy, in so far as the envious man sees his neighbor prosper notwithstanding his efforts to prevent it. On the other hand, "joy at another's misfortune" is not directly the same as envy, but is a result thereof, because grief over our neighbor's good which is envy, gives rise to joy in his evil.