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).
Holy See
Notwithstanding, the Holy See was represented in and identified as a "permanent subject of general customary international law vis-à-vis all states" in the Congress of Vienna of 1814 to 1815. The Papal States were recognised under the rule of the Papacy and largely restored to their former extent. Despite the Capture of Rome in 1870 by the Kingdom of Italy and the Roman Question during the Savoyard era (which made the Pope a "prisoner in the Vatican" from 1870 to 1929), its international legal subject was "constituted by the ongoing reciprocity of diplomatic relationships" that not only were maintained but multiplied.