It is well known that we fight in God's cause... but unless God helps us by a miracle the English, who have faster and handier ships than ours, and many more long-range guns, and who know their advantage just as well as we do, will never close with us at all, but stand aloof and knock us to pieces with their culverins, without our being able to do them any serious hurt. So we are sailing against England in the confident hope of a miracle.

The impossibility of keeping Englishmen sober ashore was a constant source of complaint, It was the great weakness of 16th century English infantrymen, whose performance when sober was admired even by the Spaniards. Already it was true, as it was to be for centuries, that many saw and despised the drunken sailor ashore, but few knew and admired him at his work afloat.

'A Naval History of Britain' which begins in the 7th century has to explain what it means by Britain. My meaning is simply the British Isles as a whole, but not any particular nation or state or our own day... 'Britain' is not a perfect word for this purpose, but 'Britain and Ireland' would be both cumbersome and misleading, implying an equality of treatment which is not possible. Ireland and the Irish figure often in this book, but Irish naval history, in the sense of the history of Irish fleets, is largely a history of what might have been rather than what actually happened.

Medieval England was a great military power with a sophisticated machinery of government, but her naval administration, at best improvised and for long periods missing altogether, pointed to a grave weakness: the lack of any reliable means of putting a force of warships at the disposal of the crown. Only Richard I and Henry V of all the kings of England can be said to have understood the problem and attempted to remedy it. It is no coincidence that they wer by far the most successful in war.

Naval dominance of European waters was the largest, longest, most complex and expensive project ever undertaken by the British state and society.

Its subject is the slow and erratic process by which the peoples of the British Isles learnt - and then for long periods forgot - about the 'Safeguard of the Sea', as the 15th century phrase had it, meaning the use of the sea for national defence, and the defence of those who used the sea.

In every age states of varying size and constitution and at every level of development have found naval warfare to be one of their most formidable and expensive tasks. Ships have always been large, costly and complicated, and warships much more complicated and costly than any others. Scholars are nowadays inclined to emphasize the power, wealth and sophistication of the Anglo-Saxon kingdoms, and there is not more striking illustration of this than the advanced and elaborate administrative structures of the early English navy.