The Battle of Grand Gulf was fought on April 29, 1863, during th: After the defeat of France at the end of the French Revolutionary Wars and Napoleonic Wars (1792–1815), the United Kingdom emerged as the principal naval and imperial power (with London the largest city in the world from about 1830).[75] Unchallenged at sea, British dominance was later described as Pax Britannica ("British Peace"), a period of relative peace among the great powers (1815–1914) during which the British Empire became the global hegemon and adopted the role of global policeman.[76] By the time of the Great Exhibition of 1851, Britain was described as the "workshop of the world".[77] From 1853 to 1856, Britain took part in the Crimean War, allied with the Ottoman Empire against Tsarist Russia,[78] participating in the naval battles of the Baltic Sea known as the Åland War in the Gulf of Bothnia and the Gulf of Finland, among others.[79] Following the Indian Rebellion in 1857, the British government led by Lord Palmerston assumed direct rule over India. Alongside the formal control it exerted over its own colonies, British dominance of much of world trade meant that it effectively controlled the economies of regions such as East Asia and Latin America.[80]