Before 1929, there was no Vatican. There was the Papal States, and the Holy See ruling over it for nearly a thousand years.
But, for a brief moment in 1849, the Papal States became a secular republic known as the Roman Republic, and it started with the assassination of the Minister of Justice of the papal government, Pellegrino Rossi.
The day after, November 16th in 1848, Rome was filled in the streets by uproarious crowds demanding a democratic government amongst other popular demands: lower taxes, increased spending, a declaration of war against Austria, etc.
Fearing his life, Pope Pius IX left Rome disguised as an ordinary priest and went to a fortress in Southern Italy in the Kingdom of the Two Sicilies.
In the pope’s absence, voters elected “twenty-seven owners, a banker, fifty-three jurists and lawyers, six graduates, twelve professors, two writers, twenty-one doctors, one pharmacist, six engineers, five employees, two merchants, nineteen military officers, one prior and one monsignore” to a new Roman parliament.
Later, the new Roman parliament convened a constitutional assembly on February 8th of 1849 to declare: Viva la Repubblica! A ruling triumvirate was proclaimed along with a secular republic government.
In response, Pope Pius IX asked for military help from Catholic countries, and found help from soon-to-be Emperor Napoleon III, who sent French troops to restore the Pope.
The Roman Republic withstood siege from the French for just over a month before Giuseppe Garibaldi, leader of the Italian Legion defending Rome, and the Roman Assembly met to debate three options: surrender, fight in the streets of Rome, or retreat.
Garibaldi declared: “Wherever we may be, there will be Rome!” Leaving with some 4000 troops on July 2nd, the French army entered Rome a day later and reestablished the temporal power of the Holy See.
Pope Pius IX returned to Rome in April of 1850, the Papal States whole again – at least for another 20 years, before being annexed by the Kingdom of Italy.