San Marino, officially the Republic of San Marino and traditionally the Most Serene Republic of San Marino, is the last remaining medieval Italian city state and sovereign nation, located entirely within Italy. It is the fifth smallest country in the world and traces its origins back to St Marinus, a Christian monk who founded a church on Mount Titano in 301 AD, located in San Marino, to escape Roman persecution. It is one of the oldest sovereign countries still in existence and has the oldest constitution in the world. It is led by two heads of state, the Captains Regent, which are elected every six months by the legislature, the Grand and General Council.