The wild idea of independence through the regional body
strictly speaking, it is not the constitution of a single state but an international pact between states, that as such can be split. That's why the Yugoslav Confederation vanished when Slovenia and Croatia claimed their original sovereignty, state.
The Italian regions never existed as such as sovereign states, are not born from the union of several states, nor are their legal inheritance. They are Italian state new formations, what if you have in mind. The Italian state cleverly prevented that a single region could even ideally represent a previously existed state. The previous states, Let's say the biggest, were the Kingdom of 2 Sicilie, the Papal States, Lombardy and Veneto, and a series of more or less large ducats and marquises. San Marino escaped this sad fate, which is still a sovereign state. Other territories were simply invaded without even mentioning their name, known the case of Seborga.
If we look at the current Italian regions they are mostly made up of scattered pieces of previous states, but only heterogeneous pieces. for example
