At sea the evolution of ordnance had to conform, of course, to the progress of naval architecture and the changing nature of the warfare. In the Mediterranean, where the oar-propelled galley remained for centuries the typical fighting ship, the bombard was planted in the bows, shackled to a deck-carriage upon the centre line, to give ahead fire and to supplement the effects of a powerful ram. As the galley developed, the main central gun became flanked by other bow-chasers; while on the beams and poop light wrought-iron breech-loading swivel guns formed a secondary armament whose double function was to repel boarders and to overawe its own slave-crew. In the Atlantic, where the typical fighting vessel was the lofty sailing ship, the same two different types of armament had vogue. But in this case their distribution was different; the sailing ship, with no recourse to oars for manœuvring, could not always ensure an end-on attack or defence, and had to arm herself against an enemy from any quarter. Her freedom from oars, her height, and the invention of the porthole, enabled the early “great ship” to mount a sufficiently distributed all-round armament. While her sides were pierced for ponderous bombards, her poop and forecastle bristled with the same light secondary armament as figured in the Mediterranean galley. This artillery was almost entirely for defence. Before Elizabethan days (as we have already noted) sea battles were nothing more than hand-to-hand fights; the attacking vessel was laid alongside its enemy, sails were furled, and boarding took place. If, after being swept by spherical shot from the bombards and showers of stones and dice from the mortars and periers, the boarders could carry the waist of the defending ship, they still had to capture the barricaded forecastle and poop, from whose rails a multitude of the smaller ordnance--port-pieces, fowlers, serpentines--were trained upon them and behind whose bulkheads crossbow and harquebuss were plied against them in concealment.