It has long been customary to regard naval warfare as the business of navies, and it usually still is. This creates an obvious problem, for navies, as the word is generally understood today, are instruments of the state; permanent fleets of warships, manned by professional officers and men, supported by an elaborate infrastructure and maintained from the revenues of central government. These are the normal instruments of naval warfare in the modern world, and it is easy to assume that they are the natural if not the only ones. Yet even a superficial knowledge of European history will show that navies in this sense were unusual if not unknown before the Renaissance. Byzantium and Venice have some claims to have possessed navies in something like the modern form, at some periods, but medieval naval warfare was generally conducted without navies. Historians have been reluctant to confront the fact. In the British case, Sir William Laid Clowes in the 1890s began his history of the Royal Navy in the third century BC, though he believed that the Navy, as an institution, had been founded in the sixteenth century AD. Even a modern publisher might hesitate at so wide a discrepancy between title and contents, yet a century after Laird Clowes, the Oxford Illustrated History of the Royal Navy adopts the same approach on a slightly more modest scale, beginning eight hundred years before the foundation of the Royal Navy.