Virtue: early 13c., “moral life and conduct, moral excellence,” vertu, from Anglo-Fr. and O.Fr. vertu, from L. virtutem (nom. virtus) “moral strength, manliness, valor, excellence, worth,” from vir “man”. Phrase by virtue of (early 13c.) preserves alternative M.E. sense of “efficacy.” Wyclif Bible has virtue where K.J.V. uses power. The seven cardinal virtues (early 14c.) were divided into the natural (justice, prudence, temperance, fortitude) and the theological (hope, faith, charity).