ἐν πιθήκοις ὄντα δεῖ εἶναι πίθηκον → in Rome we do as the Romans do | when in Rome, do as the Romans do | when in Rome, do as the Romans | when in Rome, do like the Romans do | when in Rome | being among monkeys one has to be a monkey
quingentēsĭmus: a, um, adj. id.,
I the five hundredth (class.): annus, Cic. Fl. 1, 1; so Plin. 15, 1, 1, § 2.
quīngentēsĭmus,¹⁴ a, um, cinq centième : Cic. Fl. 1.