Question: When did the place where the author of Princeps Pastorum died become its own country?

Knowledge 1: Canonization of Pope John XXIII and Pope John Paul II
Pope John XXIII (25 November 1881 – 3 June 1963) and Pope John Paul II (18 May 1920 – 2 April 2005) reigned as popes of the Roman Catholic Church and the sovereigns of Vatican City (respectively from 1958 to 1963 and 1978 to 2005). Their canonizations were held on 27 April 2014. The decision to canonize was made official by Pope Francis on 5 July 2013 following the recognition of a miracle attributed to the intercession of John Paul II, while John XXIII was canonized for his merits of opening the Second Vatican Council. The date of the canonization was assigned on 30 September 2013. [SEP] Knowledge 2: Vatican City
The name Vatican city was first used in the Lateran Treaty, signed on 11 February 1929, which established the modern city - state. The name is taken from Vatican Hill, the geographic location of the state. ``Vatican ''is derived from the name of an Etruscan settlement, Vatica or Vaticum meaning garden, located in the general area the Romans called vaticanus ager,`` Vatican territory''. [SEP] Knowledge 3: Princeps pastorum
Princeps pastorum (Latin for 'Prince of the shepherds') is the title of an encyclical letter promulgated by Pope John XXIII on 28 November 1959. It is derived from a biblical passage: I Peter 5:4. In its English translation the letter opens with the phrase "On the day when "the Prince of the shepherds" entrusted to Us His lambs and sheep". It refers to Jesus Christ.
Knowledge 1: Princeps pastorum
Princeps pastorum (Latin for 'Prince of the shepherds') is the title of an encyclical letter promulgated by Pope John XXIII on 28 November 1959. It is derived from a biblical passage: I Peter 5:4. In its English translation the letter opens with the phrase "On the day when "the Prince of the shepherds" entrusted to Us His lambs and sheep". It refers to Jesus Christ. [SEP] Knowledge 2: Canonization of Pope John XXIII and Pope John Paul II
Pope John XXIII (25 November 1881 – 3 June 1963) and Pope John Paul II (18 May 1920 – 2 April 2005) reigned as popes of the Roman Catholic Church and the sovereigns of Vatican City (respectively from 1958 to 1963 and 1978 to 2005). Their canonizations were held on 27 April 2014. The decision to canonize was made official by Pope Francis on 5 July 2013 following the recognition of a miracle attributed to the intercession of John Paul II, while John XXIII was canonized for his merits of opening the Second Vatican Council. The date of the canonization was assigned on 30 September 2013. [SEP] Knowledge 3: Vatican City
The name Vatican city was first used in the Lateran Treaty, signed on 11 February 1929, which established the modern city - state. The name is taken from Vatican Hill, the geographic location of the state. ``Vatican ''is derived from the name of an Etruscan settlement, Vatica or Vaticum meaning garden, located in the general area the Romans called vaticanus ager,`` Vatican territory''.
Knowledge 1: Canonization of Pope John XXIII and Pope John Paul II
Pope John XXIII (25 November 1881 – 3 June 1963) and Pope John Paul II (18 May 1920 – 2 April 2005) reigned as popes of the Roman Catholic Church and the sovereigns of Vatican City (respectively from 1958 to 1963 and 1978 to 2005). Their canonizations were held on 27 April 2014. The decision to canonize was made official by Pope Francis on 5 July 2013 following the recognition of a miracle attributed to the intercession of John Paul II, while John XXIII was canonized for his merits of opening the Second Vatican Council. The date of the canonization was assigned on 30 September 2013. [SEP] Knowledge 2: Heresy
Within six years of the official criminalization of heresy by the Emperor, the first Christian heretic to be executed, Priscillian, was condemned in 386 by Roman secular officials for sorcery, and put to death with four or five followers. However, his accusers were excommunicated both by Ambrose of Milan and Pope Siricius, who opposed Priscillian's heresy, but "believed capital punishment to be inappropriate at best and usually unequivocally evil". For some years after the Reformation, Protestant churches were also known to execute those they considered heretics, including Catholics. The last known heretic executed by sentence of the Roman Catholic Church was Spanish schoolmaster Cayetano Ripoll in 1826. The number of people executed as heretics under the authority of the various "ecclesiastical authorities"[note 1] is not known.[note 2] One of the first examples of the word as translated from the Nag Hammadi's Apocalypse of Peter was" they will cleave to the name of a dead man thinking that they will become pure. But they will become greatly defiled and they will fall into the name of error and into the hands of an evil cunning man and a manifold dogma, and they will be ruled heretically". [SEP] Knowledge 3: Princeps pastorum
Princeps pastorum (Latin for 'Prince of the shepherds') is the title of an encyclical letter promulgated by Pope John XXIII on 28 November 1959. It is derived from a biblical passage: I Peter 5:4. In its English translation the letter opens with the phrase "On the day when "the Prince of the shepherds" entrusted to Us His lambs and sheep". It refers to Jesus Christ.

Answer: 11 February 1929