San Marino, officially the Republic of San Marino, is a country situated on the eastern side of the Apennine Mountains. It is an enclave in Italy. Its size is just over 61 km2 (24 sq mi) with an estimated population of over 30,000. Its capital is the City of San Marino. One of the European microstates, along with Liechtenstein, the Vatican, Monaco, Andorra, and Malta, San Marino has the smallest population of all the members of the Council of Europe.
San Marino is the oldest surviving sovereign state and constitutional republic in the world, as the continuation of the monastic community founded on 3 September 301, by stonecutter Marinus of Arbe. Legend has it that Marinus left Rab, then the Roman colony of Arba, in 257 when the future emperor, Diocletian, issued a decree calling for the reconstruction of the city walls of Rimini, which had been destroyed by Liburnian pirates.