A Marriage made in Heaven
https://en.wikipedia.org/wiki/Reichskonkordat
The Reichskonkordat ("Concordat between the Holy See and the German Reich"[1]) is a treaty negotiated between the Vatican and the emergent Nazi Germany.
It was signed on 20 July 1933 by Cardinal Secretary of State Eugenio Pacelli, who later became Pope Pius XII, on behalf of Pope Pius XI and Vice Chancellor Franz von Papen on behalf of President Paul von Hindenburg and the German government.
It was ratified 10 September 1933 and it has been in force from that date onward. The treaty guarantees the rights of the Catholic Church in Germany.
When bishops take office Article 16 states they are required to take an oath of loyalty to the Governor or President of the German Reich established according to the constitution.
The treaty also requires all clergy to abstain from working in and for political parties.
Nazi breaches of the agreement began almost as soon as it had been signed and intensified afterwards leading to protest from the Church including in the 1937 Mit brennender Sorge encyclical of Pope Pius XI.
The Nazis planned to eliminate the Church's influence by restricting its organizations to purely religious activities.[2]
The Reichskonkordat is the most controversial of several concordats that the Vatican negotiated during the pontificate of Pius XI.
It is frequently discussed in works that deal with the rise of Hitler in the early 1930s and the Holocaust.
The concordat has been described by some as giving moral legitimacy to the Nazi regime soon after Hitler had acquired quasi-dictatorial powers through the Enabling Act of 1933, an Act itself facilitated through the support of the Catholic Centre Party.
The treaty places constraints on the political activity of German clergy of the Catholic Church. Following the passage of the 1935 Nuremberg Laws for example, a policy of nonintervention was followed.
The majority of the German church hierarchy regarded the treaty as a symbol of peace between church and state.[3]
From a Catholic church perspective it has been argued that the Concordat prevented even greater evils being unleashed against the Church.[4]
Though some German bishops were unenthusiastic, and the Allies at the end of World War II felt it inappropriate, Pope Pius XII successfully argued to keep the concordat in force.
It is still in force today.
https://www.jstor.org/stable/24456869
Concordat Between the Holy See and the German Reich
July 20, 1933
His Holiness Pope Pius XI and the President of the German Reich, moved by a common desire to consolidate and enhance the friendly relations existing between the Holy See and the German Reich,
wish to regulate the relations between the Catholic Church and the State for the whole territory of the German Reich in a permanent manner and on a basis acceptable to both parties.
They have decided to conclude a solemn agreement, which will supplement the Concordats already concluded with certain individual German states, and will ensure for the remaining States fundamentally uniform treatment of their respective problems.
For this purpose:
His Holiness Pope Pius XI has appointed as his Plenipotentiary His Eminence the Most Reverend Lord Cardinal Eugenio Pacelli, his Secretary of State.
The President of the German Reich has appointed as Plenipotentiary the Vice-Chancellor of the German Reich, Herr Franz von Papen.
https://www.newadvent.org/library/docs_ss33co.htm