The issue of the Post Agreement with The Sovereign Order of the Knights of Saint John was published in the memory of signing the bilateral agreement between the Post Administration of the Slovak Republic and the Post Administration of The Sovereign Order of the Knights of Saint John on transport and delivery of letters within the area of the Slovak Republic that has been valid since October 15.th 1999. The Sovereign Order of the Knights of Saint John is one of the oldest and most famous sovereign orders with rich history reaching to the present time. Its establishment is connected with the conquest of Jerusalem by the crusade in 1099 and it continued with the activities developed from the beginning of the 11th century in Jerusalem by The Hospital Brotherhood of Italian Pilgrims looking after the sick. The patron of The Sovereign Order of the Knights of Saint John is St. John the Babtist. The head of The Sovereign Order is the High Master, who is directly inferior in authority to the Pope and at the same time he has the position of the head of state. He is elected by the Big State Council consisting of the representatives of all member classes and order assemblies. The main role of The Sovereign Order of the Knights of Saint John is to carry out charity activities.