There was a time in which The Pope commanded a first-class army; an army full of might and power. By the late 1860's however, The Papal States were reduced to a shadow of its former self. Decades of French and Austrian meddling in its affairs, had left it a corpse ripe of the picking.
In comes 1870, The Papal States had been propped by the French King Napoleon III. Napoleon III gets his arse handed to him in a silver platter after he is captured in The Battle of Sedan. Bismark dances over Versailles, and Paris is soon to erupt into a proto-Communist revolt.
In this vacuum, The Papal States almost fall into an anarchist revolt. This forced the Italian Armies of Vittorio II to take over Rome, and send the Pope into a 50 year "exile" inside the walls of the Vatican.
But before all of this happened, there was one last "Pass-in-Review" held for the Papal Army. Below is the only photograph that I know-of, of the Papal Army assembled together.

There are two captions in this picture. The first one reads:
Pope Pius IX - Rome April 25th 1870.
From St. Peter's Basilica: (The Pope) imparts the last blessing to his loyal troops comprised of 20,000 French and Swiss (soldiers).
The second caption reads:
Sept. 20th 1870. The Italians entered Rome, Expelling the foreigners.
Boq



There was also a Pontifical Navy, now long forgotten, that was the first line of defence against Muslim terror-....errrr, pirates, (yeah, that's it....) in the 9th or 10th Century.