Faithless and fatal truces.
The Emperor Antonius Caracalla destroyed the citizens of Alexandria, at one time, and at another cut off the attendants of Artabanus, King of Persia, under colour of marrying his daughter.
Jacob's children destroyed the Shechemites to avenge the rape of Dinah. Gallienus, the Roman Emperor, put to death the military men in Constantinople. Antonius, under colour of friendship, enticed Artavasdes of Armenia; then, binding him in heavy chains, put him to death.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894