The historical figure acknowledged for his role in unifying Italy is Giuseppe Garibaldi. Often referred to as the "Hero of Two Worlds," Garibaldi was a key figure in the Italian unification movement during the 19th century. His military campaigns and leadership in the unification process were instrumental in declaring the Kingdom of Italy in 1861. Garibaldi's dedication to the cause of unification and his commitment to republican ideals made him a symbol of Italian nationalism and an enduring figure in Italy's history.