“When among madmen, you should act completely mad.”
μετὰ μαινομένων φάσιν χρῆναι μαίνεσθαι πάντας ὁμοίως
This is the “When in Rome…” of Old Comedy
Callias, fr. 25 (Clement of Alexandria, Miscellanies 6.12.5)
ΕΥΔΟΞΑ ΑΓΝΩΣΤΑ ΚΑΤΑΓΕΛΑΣΤΑ