Allemand's expedition of 1805, often referred to as the Escadre invisible (invisible squadron) in French sources, was an important French naval expedition during the Napoleonic Wars, which formed a major diversion to the ongoing Trafalgar Campaign in the Atlantic Ocean. With the French Mediterranean Fleet at sea, Emperor Napoleon I hoped to unite it with the French Atlantic Fleet and together form a force powerful enough to temporarily displace the British Royal Navy Channel Fleet for long enough to allow an invasion force to cross the English Channel and land in Britain. In support of this plan, the French squadron based at Rochefort put to sea in July 1805, initially with the intention that they would join the Atlantic Fleet from Brest. When this fleet failed to put to sea, the Rochefort