The oracle of Delphi, the sacred abode of the raving prophetess, the Pythia, was for centuries one of the most celebrated and influential religious centers in the ancient Greek world. There, the magnificent temple of Apollo was not only gilded in riches of gold and bronze but also in the jewels of everlasting wisdom: the Delphic Admonitions. These were brief "catchphrases" conveying moral, philosophical and even practical teachings, inscribed on pillars around the temple. They were attributed to the Seven Sages of antiquity, a group of philosophers who laid the cornerstone in the edifice of...