woe to the vanquished

From LSJ

μηδείς ἀγεωμέτρητος εἰσίτω μου τὴν στέγην → let no one ignorant of geometry come under my roof

Source

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.