1463-2013. That is 550 years of history. An anniversary that sees as protagonists two States, two peoples and a common tension towards freedom and the fraternal sharing of ideals and values. To be celebrated with this joint Italy - San Marino issue is not only the historical anniversary of the ‘Patti di Fossombrone’ (1463) through which the Titan obtained the castles of Montegiardino, Fiorentino, Serravalle and later also Faetano, thus reaching the current territorial area, but a real eulogy to the concept of Sovereignty. The sheet created by Marco Biordi, containing four stamps, is a true sui generis “archive” of that Papal Bull with which His Holiness Pius II ratified the clauses of previous agreements between the Community of San Marino and the Cardinal Legate of the Pope. Marco Biordi's work was a true “research” document, where the perforation lines of the stamps also represent the parallels and meridians of the cartographic system used, making the sheet a sort of geo-referenced philatelic issue.