ὀδύνη τοῖς νενικημένοις
From LSJ
μεγάλα ὠφελήσεσθε πρὸς ἱστορίαν τῶν κοινῶν → that will be of great benefit to you in order to understand public affairs
Wikipedia EN
Vae victis (IPA: [ˈwae̯ ˈwɪktiːs]) is Latin for "woe to the vanquished", or "woe to the conquered". It means that those defeated in battle are entirely at the mercy of their conquerors and should not expect—or request—leniency.