Napoleon's planned invasion of the United Kingdom at the start of the War of the Third Coalition, although never carried out, was a major influence on British naval strategy and the fortification of the coast of southeast England. French attempts to invade Ireland in order to destabilise the United Kingdom or as a stepping-stone to Great Britain had already occurred in 1796. From 1803 to 1805 a new army of 200,000 men, known as the Armée des côtes de l'Océan was gathered and trained at camps at Boulogne, Bruges and Montreuil. A large "National Flotilla" of invasion barges was built in Channel ports along the coasts of France and the Netherlands right from Étaples to Flushing, and gathered at Boulogne. These preparations were financed by the Louisiana Purchase of 1803, whereby France ceded her huge North American territories to the United States in return for a payment of 50 million French francs ($11,250,000). The entire amount was spent on the projected invasion.