ξένος ὢν ἀκολούθει τοῖς ἐπιχωρίοις νόμοις → as a foreigner, follow the laws of that country | when in Rome, do as the Romans do
quĭănĕ, est-ce parce que ? la raison serait-elle que ? Pl. Pers. 851 ; Virg. En. 4, 538.