Brewer's: Cry Havock!
No quarter. In a tract entitled The Office of the Constable and Mareschall in the Tyme of Werre (contained in the Black Book of the Admiralty), one of the chapters is, “The peyne of hym that crieth havock, and of them that followeth him”—“Item si quis inventus fuerit qui clamorem inceperit qui vocatur havok. ”
“Cry Havock, and let slip the dogs of war.”
Shakespeare: Julius Cæsar, iii. 1