Late 16th century; earliest use found in John Lyly (1554–1606), writer and playwright. From (i) classical Latin Panathēnaea festival at Athens, and its etymon (ii) ancient Greek Παναθήναια, use as noun (short for Παναθήναια ἱερά Panathenian solemnities) of neuter plural of Παναθηναῖος from παν- + Ἀθηναῖος Athenian from either Ἀθῆναι Athens, or Ἀθήνη Athene, the patron goddess of Athens + -ιος, suffix forming adjectives.