The beginnings of a permanent and strong naval establishment, as distinct from merchant vessels owned by the king or in his service, must be dated, however, from the Tudors and the period of national rehabilitation following the Hundred Years' War (1337-1453) and the War of the Roses (1455-1485). One reason for this was that the employment of artillery on shipboard and the introduction of port-holes made it increasingly difficult to convert merchant craft into dependable men-of-war. Henry VIII took a keen interest in his navy, devoted the revenues of forfeited church property to its expansion, established the first Navy Board (1546), and is even credited with the adoption of sailing vessels as the major units of his fleet.
The use of heavy ordnance, already mentioned, as well as the increasing size and efficiency of sail-craft that came with the spread of ocean commerce and navigation, naturally pointed the way to this transition in warfare from oar to sail. The galley was at best a frail affair, cumbered with oars, benches and rowers, unable to carry heavy guns or withstand their fire. Once sailing vessels had attained reasonable maneuvering qualities, their superior strength and size, reduced number of non-combatant personnel, and increased seaworthiness and cruising radius gave them a tremendous superiority. That the change should have begun in the north rather than in the Mediterranean, where naval and military science had reached its highest development, must be attributed not only to the rougher weather conditions of the northern seas, and the difficulty of obtaining slaves as rowers, but also to the fact that the southern nations were more completely shackled by the traditions of galley warfare.
Yet for the new type it was the splendid trading vessels of Venice that supplied the design. For the Antwerp and London trade, and in protection against the increasing danger from pirates, the Venetians had developed a compromise between the war-galley and the round-ship of commerce, a type with three masts and propelled at least primarily by sails, with a length about three times its beam and thus shorter and more seaworthy than the galley, but longer, lower and swifter than the clumsy round-ship. To this new type the names _galleass_ and _galleon_ were bath given, but in English and later usage _galleass_ came to be applied to war vessels combining oar and sail, and _galleon_ to either war or trading vessels of medium size and length and propelled by sail alone.