The effect of the expulsion of James II from the throne of England coupled with the accession of the Dutch prince, William of Orange, was to make England change sides and take the leadership in the coalition opposed to Louis XIV. From this time on, for over 125 years, England was involved in a series of wars with France. They began with the threat of Louis to dominate Europe and ended with the similar threat on the part of Napoleon. In all this conflict the sea power of England was a factor of paramount importance. Even when the fighting was continental rather than naval, the ability of Great Britain to cut France off from her overseas possessions resulted in the transfer of enormous tracts of territory to the British Empire. During the 18th century, the territorial extent of the expire grew by leaps and bounds, with the single important loss of the American colonies. And even this brought no positive advantage to France for it did not weaken her adversary's grip on the sea. _The War of the League of Augsburg_ The accession of William III was the signal for England's entry into the war of the League of Augsburg (1688-1697) against France, and the effort of the French king to put James II back again upon the English throne. By this time the French navy had been so greatly strengthened that at the outset it outnumbered the combined fleets of the English and the Dutch. It boasted the only notable admiral of this period, Tourville, but it missed every opportunity to do something decisive. It failed to keep William from landing in England with an army; it failed also to keep the English from landing and supplying an army in Ireland, where they raised the siege of Londonderry and won the decisive victory of the Boyne. On the other hand the British navy was handled with equal irresolution and blindness in strategy. It accomplished what it did in keeping communications open with Ireland through the mistakes of the French, and its leaders seemed to be equally unaware of the importance of winning definitely the control of the sea. [Illustration: THREE-DECKED SHIP OF THE LINE, 18TH CENTURY]