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,
Aragonese conquest of Sardinia of Castelsardo (at that time called "Casteldoria" or "Castelgenovese"), which had been stolen from the Doria in 1448. The subduing of Sardinia having taken a century, Corsica, which had never been wrestled from the Genoese, was dropped from the formal title of the Kingdom. Aragonese conquest of Sardinia The Aragonese conquest of Sardinia took place between 1323 and 1326. The island of Sardinia was at the time subject to the influence of the Republic of Pisa, the pisan della Gherardesca family, Genoa and of the genoese families of Doria and the Malaspina; the only native political entity survived was the