Italian Unification (24 January 1859)
Historical Map of Europe & the Mediterranean
By the late 1850s, the cause of Italian unification was drawing widespread support from intellectuals and radicals across Europe. After narrowly surviving an assassination attempt by one such group, Napoleon III of France decided he would secretly back the Kingdom of Sardinia in an attempt to unite northern Italy (in return for territorial concessions, of course).
In May 1857, Indian soldiers ("Sepoys") revolted against their British commanders in protest of rule over the country by the British East India Company. The revolt expanded across northern India and lasted over a year before being crushed, formally ending the Mughal Empire and transferring control of the subcontinent to the British Crown.
Prussia renounces sovereignty over Swiss Canton of Neuchâtel
The continuing dispute over Neuchâtel caused a short-lived royalist revolt in 1856, leading the Great Powers to pressure Prussia into renouncing its sovereignty over the canton.
On 14 January 1858, Italian nationalist Felice Orsini attempted to assassinate Napoleon III in Paris, believing that Napoleon was obstructing the cause of Italian unification. Although the attempt was unsuccessful, the incident caused major political uproar in Italy and in Britain, where Orsini had previously sought asylum and worked as a lecturer.
Treaty of alliance between France and Sardinia
Following the attempt on his life by Orsini, Napoleon III of France agreed to secretly support Sardinia's attempt to unite northern Italy, in exchange for plebiscites on French sovereignty over Savoy and Nice.
In accordance with the 1856 Treaty of Paris, Moldavia and Wallachia held elections for ad-hoc divans, who in 1859 voted to unite the two principalities under the rule of Dominitor Alexandru Ioan Cuza.