Cardinal Secretary of State in the context of "Reichskonkordat"

Pope Pius XII (Italian: Pio XII; born Eugenio Maria Giuseppe Giovanni Pacelli; 2 March 1876 – 9 October 1958) was head of the Catholic Church and sovereign of the Vatican City from 2 March 1939 until his death on 9 October 1958. He is the most recent pope to take the pontifical name "Pius".

The papacy of Pius XII was long, even by modern standards; it lasted almost 20 years, and spanned a consequential fifth of the 20th century. Pius was a diplomat pope during the destruction wrought by the Second World War, the recovery and rebuilding which followed, the beginning of the Cold War, and the early building of a new international geopolitical order, which aimed to protect human rights and maintain global peace through the establishment of international rules and institutions (such as the United Nations). Born, raised, educated, ordained, and resident for most of his life in Rome, his work in the Roman Curia—as a priest, then bishop, then cardinal—was extensive. He served as secretary of the Vatican's diplomatic Department of Extraordinary Ecclesiastical Affairs, papal nuncio to Germany, Camerlengo of the Apostolic Chamber, and Cardinal Secretary of State for the Holy See, in which capacity he worked to conclude treaties with various European and Latin American nations, including the Reichskonkordat treaty with Nazi Germany.

The Secretariat of State (Latin: Secretaria Status; Italian: Segreteria di Stato) is the oldest dicastery in the Roman Curia, the central papal governing bureaucracy of the Catholic Church. It is headed by the Cardinal Secretary of State and performs all the political and diplomatic functions of the Holy See. The Secretariat is divided into three sections: the Section for General Affairs, the Section for Relations with States, and, since 2017, the Section for Diplomatic Staff.

Domenico Tardini (29 February 1888 – 30 July 1961) was a longtime aide to Pope Pius XII in the Secretariat of State. Pope John XXIII named him Cardinal Secretary of State and, in this position the most prominent member of the Roman Curia in Vatican City.

A cardinal-nephew (Latin: cardinalis nepos; Italian: cardinale nipote; Spanish: valido de su tío; Portuguese: cardeal-sobrinho; French: prince de fortune) was a cardinal elevated by a pope who was that cardinal's relative. The practice of creating cardinal-nephews originated in the Middle Ages, and reached its apex during the 16th and 17th centuries. The last cardinal-nephew was named in 1689 and the practice was abolished in 1692. The word nepotism originally referred specifically to this practice, when it appeared in the English language about 1669. From the middle of the Avignon Papacy (1309–1377) until Pope Innocent XII's anti-nepotism bull (a papal charter), Romanum decet pontificem (1692), a pope without a cardinal-nephew was the exception to the rule. Every Renaissance pope who created cardinals appointed a relative to the College of Cardinals, and the nephew was the most common choice, although one of Alexander VI's creations was his own son.

The institution of the cardinal-nephew evolved over seven centuries, tracking developments in the history of the papacy and the styles of individual popes. From 1566 until 1692, a cardinal-nephew held the curial office of the Superintendent of the Ecclesiastical State, known as the Cardinal Nephew, and thus the terms are sometimes used interchangeably. The curial office of the Cardinal Nephew as well as the institution of the cardinal-nephew declined as the power of the Cardinal Secretary of State increased and the temporal power of popes decreased in the 17th and 18th centuries.

Pietro Gasparri GCTE (5 May 1852 – 18 November 1934) was a Roman Catholic cardinal, diplomat and politician in the Roman Curia and the signatory of the Lateran Pacts. He served also as Cardinal Secretary of State under Popes Benedict XV and Pope Pius XI.