War of the Quadruple Alliance

The Battle of Cape Passaro, fought on 11–12 August 1718 off the southern tip of Sicily, was a naval engagement between a Royal Navy fleet under Admiral Sir George Byng and a Spanish fleet under Lieutenant-General José Antonio de Gaztañeta. Spain suffered approximately 2,400 casualties in the action. The battle occurred while Spain and Britain were formally at peace, making it a preemptive British strike rooted in Britain's existing commitment to supporting Emperor Charles VI's ambitions in southern Italy. Sicily had been occupied by Spain, and Byng's intervention was directed at frustrating Spanish military operations in the region. The engagement effectively destroyed Spanish naval capacity in the theater and preceded Britain's formal entry into the War of the Quadruple Alliance, placing the battle at the opening of a conflict in which the major European powers moved to contain Spanish ambitions in Italy under Philip V. As an act of war conducted before any declaration, Cape Passaro illustrated the degree to which British strategic interests were already aligned against Spain's Mediterranean expansion prior to the formal coalescence of the Quadruple Alliance.