The Most Serene Republic of San Marino (Italian: Serenissima Repubblica di San Marino) is a country in the Apennine Mountains. It is a landlocked enclave, completely surrounded by Italy. One of the European microstates, San Marino has the smallest population of all the members of the Council of Europe. San Marino claims to be the oldest constitutional republic in the world: it was founded on September 3 in the year 301 by Marinus of Rab, a Christian stonemason fleeing the religious persecution of Roman Emperor Diocletian. San Marino's constitution, dating back to 1600, is the world's oldest written constitution still in effect.