Gibraltar-Vatican Joint Issue
The Vatican City State issued its first stamps in 1929, the same year that it was established under the Lateran Treaties. It released its first joint issue in 1969. Joint issues of stamps by the Vatican and other countries were uncommon for most of the twentieth century. In 2000, the Vatican and Poland released a joint issue designed by Czeslaw Slania which commemorated the eightieth birthday of John Paul II. However, the early twenty-first century saw a substantial increase in joint issues. In 2003, a set released by the Vatican and Poland celebrated the twenty-fifth anniversary of John Paul II's pontificate. The following year, a joint issue of the same countries commemorated the pope's return visits to Poland. In 2005, five of the eleven stamp sets released by the Vatican were joint issues. There have also been joint issues with Germany since Benedict XVI became Pope. In 2011, the Vatican and Croatia released a joint issue which commemorated the tercentenary of the birth of Rugerius Boscovich (1711 – 1787).
Foreign relations of the Holy See
The Holy See, as a non-state sovereign entity and full subject of international law, started establishing diplomatic relations with sovereign states in the 15th century. It had the territory of the States of the Church under its direct sovereign rule since centuries before that time. Currently it has the territory of the State of the Vatican City under its direct sovereign rule. In the period of 1870-1929 between the annexation of Rome by the Kingdom of Italy and the ratification of the Lateran Treaty establishing the current Vatican City State, the Holy See was devoid of territory. In this period some states suspended their diplomatic relations, but others retained them (or established such relations for the first time or reestablished them after a break), so that the number of states that did have diplomatic relations with the Holy See almost doubled (from 16 to 27) in the period between 1871 and 1929.