What events caused the unification of Italy? explain what happened

Italian unification (Italian: Unificazione italiana), or the Risorgimento meaning resurgence or revival), was the political and social movement that consolidated different states of the Italian peninsula into the single state of the Kingdom of Italy in the 19th century. The process began in 1815 with the Congress of Vienna and was completed in 1871 when Rome became the capital of the Kingdom of Italy. The memory of the Risorgimento is central to both Italian politics and Italian historiography, for this short period (1815-60) is one of the most contested and controversial in modern Italian history. Italian nationalism was based among intellectuals and political activists, often operating from exile.