The Roman Republic (Italian: Repubblica Romana) was a short-lived state declared on 9 February 1849, when the government of the Papal States was temporarily replaced by a republican government due to Pope Pius IX's departure to Gaeta. The republic was led by Carlo Armellini, Giuseppe Mazzini, and Aurelio Saffi. Together they formed a triumvirate, a reflection of a form of government in the ancient Roman Republic.

One of the major innovations the Republic hoped to achieve was enshrined in its constitution: Freedom of religion, with Pope Pius IX and his successors guaranteed the right to govern the Catholic Church. These religious freedoms were quite different from the situation under the preceding government, which allowed only Catholicism and Judaism to be practiced by its citizens. The Constitution of the Roman Republic was the first in the world to abolish capital punishment in its constitutional law.