Question: When did the Governorship end of the city where the author of Paenitentiam Agere died?

Knowledge 1: Paenitentiam agere
Paenitentiam agere ("Penance for sins") was the seventh encyclical made by Pope John XXIII, and was issued on 1 July 1962. It calls on Christians to practice penance and considers the upcoming Second Vatican Council. [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: Governor of Vatican City
The post of Governor of Vatican City (Governatore dello Stato della Città del Vaticano in Italian) was held by Marchese Camillo Serafini from the foundation of the state in 1929 until his death in 1952. No successor was appointed, and the post itself was not mentioned in the Fundamental Law of Vatican City State issued by Pope John Paul II on 26 November 2000, which entered into force on 22 February 2001.
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: Governor of Vatican City
The post of Governor of Vatican City (Governatore dello Stato della Città del Vaticano in Italian) was held by Marchese Camillo Serafini from the foundation of the state in 1929 until his death in 1952. No successor was appointed, and the post itself was not mentioned in the Fundamental Law of Vatican City State issued by Pope John Paul II on 26 November 2000, which entered into force on 22 February 2001. [SEP] Knowledge 3: Paenitentiam agere
Paenitentiam agere ("Penance for sins") was the seventh encyclical made by Pope John XXIII, and was issued on 1 July 1962. It calls on Christians to practice penance and considers the upcoming Second Vatican Council.
Knowledge 1: Paenitentiam agere
Paenitentiam agere ("Penance for sins") was the seventh encyclical made by Pope John XXIII, and was issued on 1 July 1962. It calls on Christians to practice penance and considers the upcoming Second Vatican Council. [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''.

Answer: 1952