San Marino, also known as the Most Serene Republic of San Marino, is a small state (and a European microstate) in Southern Europe enclaved by Italy.
Saint Marinus left the island of Rab in present-day Croatia with his lifelong friend Leo, and went to the city of Rimini as a stonemason. After the Diocletianic Persecution following his Christian sermons, he escaped to the nearby Monte Titano, where he built a small church and thus founded what is now the city and state of San Marino.

The official founding date is 3 September 301. In 1320 the community of Chiesanuova chose to join the country. In 1463 San Marino was extended with the communities of Faetano, Fiorentino, Montegiardino, and Serravalle, after which the country's borders have remained unchanged.
San Marino is the world's smallest republic, although when Nauru gained independence in 1968 it challenged that claim, Nauru's land mass being only 21 km2. However Nauru's jurisdiction over its surrounding waters covers 431,000 km2, an area thousands of times greater than the territory of San Marino. 
San Marino became a member of the Council of Europe in 1988 and of the United Nations in 1992. It is not a member of the European Union, although it uses the euro as its currency (despite not legally being part of the Eurozone).

According to en.wikipedia

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