Giuseppe Mazzini (June 22, 1805 – March 10, 1872) was an Italian writer and politician whose efforts helped bring about the modern Italian state, rather than the medley of separate states, many dominated by foreign powers, that existed in the nineteenth century.

Born in Genoa, he became a member of the Carbonari in 1830, a secret association with political purposes. His activity in revolutionary movements soon caused him to be proscribed and in 1831 he went to Marseilles, where he organized a new political society called Giovane Italia (Young Italy), whose watchword was God and the People and whose basic principle was the union of the several states and kingdoms of the peninsula into one republic as the only true foundation of Italian liberty. He also founded several similar organizations aimed at the unification or liberation of other nations: Young Germany, Young Poland and finally Young Europe (Giovane Europa).

Mazzini believed that Italian unification could only be achieved through a popular uprising. He continued to avow this purpose in his writings and pursued it through exile and adversity with inflexible constancy. However, his importance was more ideological than practical: after the failure of the 1848 revolutions (during which Mazzini became the main leader of the short-lived Roman Republic), the Italian nationalists began to look to the king of Sardinia and his prime minister Count Cavour as the leaders of the unification movement. This meant separating national unification from the social and political reforms advocated by Mazzini.

Cavour was able to secure an alliance with France, leading to a series of wars between 1859 and 1861 that culminated in the formation of a unified kingdom of Italy. General Giuseppe Garibaldi, a former follower of Mazzini, also played a major role, but this kingdom was very far from the republic preached by Mazzini.

Mazzini never accepted monarchical united Italy and continued to agitate for a democratic republic. In 1870 he was arrested and sent again into exile, even though he managed to return under a false name and live in Pisa until his death in 1872. The political movement he led was called the Republican party and was active in Italy until the 1990's.

See also Roman Republic (19th century), History of Italy, Italian unification