During the dramatic events of the spring and early summer of 1849, when the French troops attacked the Roman Republic for a whole month, Porta San Pancrazio played a major role in the desperate defence of Rome led by Giuseppe Garibaldi.
In memory of that heroic resistance, for which men such as Emilio Dandolo, Luciano Manara, Goffredo Mameli gave their lives, for the 150th anniversary of the Unification of Italy, Porta San Pancrazio has become a museum dedicated to the 1849 Roman Republic and the memory of Garibaldi. A strongly evocative location and a privileged standpoint of the historical and monumental area of the Janiculum, where the memory of that battle is still presents in the monuments. The San Pancrazio gate, located on the height of the Janiculum in the perimeter of the Urbanian or Gianicolense walls, was built in 1854-57 by the architect Virginio Vespignani on the ruins of the gate created by Marcantonio De Rossi in 1648 and partially destroyed during the war of 1849. In turn, the seventeenth-century Aurelia gate had replaced the old gate in the Aurelian walls slightly behind than it does today. On April 19, 1951 the City Council designated the National Association of Veterans and the Garibaldi Veterans for the construction of the museum, which was opened in 1976 with two sections: the first on the History of the Risorgimento and Garibaldi and the second on the hustory of the Italian Garibaldi division.