This week I was on a trip to Rome. When I was there I also visited the Vatican City where I bought my first Vatican stamp sets.
The Vatican City State is a enclave in Rome and the smallest accepted state of the world (44 ha). The Head of State is the Pope, so at the moment Pope Francis. The whole territory of the Vatican City State is a UNESCO World Heritage Site. The Vatican City State arose from the Papal States and was founded in 1929 per the Lateran Treaty closed between Pope and Benito Mussolini.
One stamp set was this:
Definitives “The Sistine Chapel 1508-2008” (issued 06-03-2008)