It was formed on 15 July 1809, when the Papal States were annexed by France.

At the Congress of Vienna, the Papal States were restored to Pius VII.

Its territory is now divided between the Italian provinces of Perugia, Terni, Macerata and Viterbo.

The department was subdivided into the following arrondissements and cantons (situation in 1812):[1] Its population in 1812 was approximately 300,000, and its area was approximately 3,357 square Italian miles (11,120 square kilometers).

[1] A department called Trasimène also briefly existed as a subdivision of the Roman Republic (1798–1799), with the same territory, but with Perugia as its capital city.