But at first, even at a time when artillery of one kind or another was in common use on land, very few guns were carried afloat. Very likely the reason was that few were suitable; they were either too big, too small, or, as before suggested, could not be safely closed at the breech. Thus in the reign of Henry IV, 1399-1413, the _Christopher_, a rather important man-of-war, only carried "three iron guns with five chambers, one hand-gun, and one small barrel of powder". The barge _Mary_ (_Marie de la Tour_) carried one iron gun with two chambers and one brass gun with one chamber. Another _Mary_ (of Weymouth) had also one brass and one iron gun, the _Bernard_ had two iron guns, and a ship referred to as the _Carrake_ one. The _Christopher's_ guns are said to have been "stoked". This may possibly mean fitted with "stocks" or oaken beds, like those previously referred to, in which case her guns were probably larger and heavier than those in the other ships. The invention of port-holes was probably coincident with the adoption of really heavy artillery afloat. Before then it would not have been safe to have carried such heavy weights on the upper decks of the kind of ship then existing. The _Great Michael_ may possibly be taken as an exception, for she could hardly have had port-holes cut in her 10-foot thick sides. At the same time, since her heavy guns were probably breech-loaders, they may have been practically built into her sides, since at that time there was no such thing as training a heavy gun right or left on board ship. With the numerous batteries of small guns also carried on board ships of this period, it was quite a different matter. They were mounted on swivels on the gunwale, or in openings or ports in the fore- and after-castles as well as in the tops. Others, and among them certain wide-mouthed pieces known as "murderers", were distributed in what were known as the "cubbridge heads", or those sides of the fore- and after-castles which faced inboard and commanded the waist of the ship. Here it was to be expected an enemy's boarders would make their assault, and here--the crew having retired fore and aft--they would be mowed down by charges of all sorts of iron fragments from the "murderers". The same system of dealing with boarders lasted some time after the disappearance of the lofty "castles" at bow and stern; strong athwart-ships bulkheads being provided at bow and stern both on the upper and main decks.