Pius XI (Vatican City 1959)

Stamp Pius XI it reflects the thematic directions:

The pope (Latin: papa, from Ancient Greek: πάππας, romanized: páppas, lit. 'father') is the bishop of Rome and the visible head[a] of the worldwide Catholic Church. He is also known as the supreme pontiff, Roman pontiff, or sovereign pontiff. From the eighth century until 1870, the pope was the sovereign or head of state of the Papal States, and since 1929 of the much smaller Vatican City state.From a Catholic viewpoint, the primacy of the bishop of Rome is largely derived from his role as the apostolic successor to Saint Peter, to whom primacy was conferred by Jesus, who gave Peter the Keys of Heaven and the powers of "binding and loosing", naming him as the "rock" upon which the Church would be built. The reigning pope is Francis, who was elected on 13 March 2013.

An anniversary is the date on which an event took place or an institution was founded in a previous year, and may also refer to the commemoration or celebration of that event. For example, the first event is the initial occurrence or, if planned, the inaugural of the event. One year later would be the first anniversary of that event. The word was first used for Catholic feasts to commemorate saints. Most countries celebrate national anniversaries, typically called national days. These could be the date of independence of the nation or the adoption of a new constitution or form of government. The important dates in a sitting monarch's reign may also be commemorated, an event often referred to as a "Jubilee".