I only became aware of the existence of the Papal States through my own research.
Since the end of the Roman Empire, Italy has been a mess. There were always wars among the various small states all over the peninsula. They could only unify the Italian speaking people in the 19th century, through the creation of a masonic state, which is still a mess. The rich people from the North hate the poor people from the South and vice-versa. Culturally, it is also a disaster, since they have many dialects and groups which have to live together on a single state full of corrupt politicians. It amazes me that they still mantain a relatively good economy and nice cities.
One more surprise here, then: "Italy" is a 19th century Romantic notion invented by English classicizers besotted by their youthful grand tours of Rome, Florence, etc. and their elevation of "Renaissance Enlightenment" and humanism over what they saw as the "Dark Ages" of Catholic Christendom (sort of like the 1960s backpacking hippies invented the idea of a unified India when it only existed as such in modern political terms). Prior to 1870, the geographic area south of the Papal States was no more "Italian" than the far northeastern regions that were more Slovenian or Swiss in their culture, language, and history. (And for that matter, there were always wars among the various small states in Europe east of the Rhine River too.)
As for languages and dialects, what is now the "Italian" language is actually the dialect of Sienna in Tuscany. After "unification" (another revolutionary re-education buzzword) it was imposed on the people of the entire peninsula in a form of internal colonialism similar to the fate of Gaelic and Welsh within Great Britain.
What is erroneously called the Sicilian "dialect" (also spoken in Calabria) is a language in itself that is older than the Siennese dialect, and it had a fully developed literature and poetry preceding Dante and Boccaccio by many centuries. Also, there are sizable groups that spoke variants of Albanian and Greek well into the years after WW2.
Oh, and beware of 21st century pseudo nostalgics who say they want to revive the widespread use of the Sicilian language but won't shut up about all the trivial Arabic vocabulary residue from the Moorish occupation of the island a thousand years ago. These shameless globalists are the sort who roll out the welcome mat on the beach at Lampedusa and celebrate the conversion of ancient village churches into mosques. Cities in Italy these days may look nice to tourists, but these areas are suffering the exact same Kalergian scourge as the rest of Europe. And its economy has been taken over by the elite of the CCP. So much for the Made in Italy brand.
When one realizes that all these... oddities... trace back to the exact same insidious influence, then it all starts to make perfect sense.