What is the origin of perfidy?

Perfidy “deliberate breach of faith or trust” derives from Latin perfidia “faithlessness,” from the adjective perfidus, literally meaning “through faith” but more accurately translated as “beyond the limits of faith.” The base of perfidus is fidēs “trust, honesty, faith,” which is related to the verb fīdere “to trust,” and both terms are the source of numerous trust-related words, such as confidence, defiance, fealty, and fidelity. Perfidy was first recorded in English in the late 1500s.