Sardinia world (22 centenarians/100,000 inhabitants). Sardinia is the first discovered Blue Zone, a demographic and/or geographic area in the world with an oversize concentration of centenarians and supercentenarians. In 2016 there were 50,346 foreign national residents, forming 3% of the total Sardinian population. The most represented nationalities were: Sardinia's most populated cities are Cagliari and Sassari. The Metropolitan City of Cagliari has 431,302 inhabitants, or about ¼ of the population of the entire island. Eurostat has identified in Sardinia two Functional Urban Areas: Cagliari, with 477,000 inhabitants, and Sassari, with 222,000 inhabitants. Sardinia is one of the five Italian autonomous regions,
Kingdom of Sardinia when the new Kingdom of Sardinia and Corsica defeated the Arborea Judicatus in a battle in Sanluri and its sovereign rights were sold by the last Judex. Later, the title of King of Sardinia was granted by the Emperor of the Holy Roman Empire to Barisone II of Arborea and Enzio of Sardinia. The first could not reunify the island under his rule, despite years of war against the other Sardinian judices, and he finally concluded a peace treaty with them in 1172. The second did not have the opportunity. Invested with the title from his father, Emperor Frederick II