Pope Pius XI and Judaism
The relations between Pope Pius XI and Judaism are generally regarded as good, as the antebellum pontiff was particularly opposed to antisemitism. Certain favourable opinions of Pius XI were subsequently used to attack the perceived silence of Pope Pius XII, whom Achille Ratti regarded as his designated successor.
Opus sacerdotale Amici Israel 
The Opus sacerdotale Amici Israel was an interfaith organization which operated within the Catholic Church from 1926 to 1928. Its first request to the Church was that the word "perfidis", which described the Jews during the Good Friday Prayer for the Jews, be removed. Pope Pius XI was reportedly strongly in favour of the reforms and asked the Congregation of Rites to review the matter. Cardinal Schuster, who was among the Friends of Israel, was appointed to monitor this issue. The Roman Curia, however, is reported to have reacted very negatively to the proposal on the basis that if one change was made to the old liturgy it would open the door to other such proposals. The Congregation for the Doctrine of the Faith decided to dissolve the association (25 March 1928).
Letter from Edith Stein 
Edith Stein was a German-Jewish philosopher, a saint of the Catholic Church, who died at Auschwitz. In April 1933 she wrote a letter to Pope Pius XI, in which she denounced the Nazi regime and asked the Pope to openly denounce the regime "to put a stop to this abuse of Christ's name."
|“||As a child of the Jewish people who, by the grace of God, for the past eleven years has also been a child of the Catholic Church, I dare to speak to the Father of Christianity about that which oppresses millions of Germans. For weeks we have seen deeds perpetrated in Germany which mock any sense of justice and humanity, not to mention love of neighbor. For years the leaders of National Socialism have been preaching hatred of the Jews. But the responsibility must fall, after all, on those who brought them to this point and it also falls on those who keep silent in the face of such happenings.
Everything that happened and continues to happen on a daily basis originates with a government that calls itself "Christian." For weeks not only Jews but also thousands of faithful Catholics in Germany, and, I believe, all over the world, have been waiting and hoping for the Church of Christ to raise its voice to put a stop to this abuse of Christ’s name." —Edith Stein, Letter to Pope Pius XI.
Martin Rhonheimer asserts that "Questioning the legitimacy of the Nazis’ racial policy, and possibly even slowing it down, required the condemnation from the very start of measures that discriminated against Jews and deprived them of their rights—as well as condemnation of the regime that instituted such measures. This is precisely what Edith Stein, bitterly aware that the German bishops were allowing themselves to be deceived, demanded of Pius XI in her now widely publicized letter of early April 1933." The timing of the letter coincides with the period when Hitler was trying to convince the bishops of his good will towards the Roman Catholic Church in order to obtain a Concordat which both sides signed in July 1933. Stein's letter received no answer, and it is not known for sure whether Pius XI even read it. William Doino asserts that Cardinal Pacelli sent a "sympathetic reply" to Stein's abbot but speculates that it may never have been received due to Nazi war time surveillance. Pacelli's reply states "I leave it to you to inform the sender [Edith Stein] in an opportune way that her letter has been dutifully presented to His Holiness [Pope Pius XI]."
Opposition to fascism, nazism and racism 
Speech to Belgian pilgrims 1938 
Ronald Rychlak notes that in September 1938 Pius XI stated:
- Mark well that in the Catholic Mass, Abraham is our Patriarch and forefather. Anti-Semitism is incompatible with the lofty thought which that fact expresses. It is a movement with which we Christians can have nothing to do. No, no I say to you it is impossible for a Christian to take part in anti-Semitism. It is inadmissible. Through Christ and in Christ we are the spiritual progeny of Abraham. Spiritually we are all Semites.
Martin Rhonheimer asserts that above passage is cited constantly for apologetics purposes but points out a line which is missing (without ellipses) in the text in which Pius asserts “We recognize the right of all people to defend themselves, to take measures against all who threaten their legitimate interests.” He comments that “It is reasonable to understand the words as meaning: legitimate defense against undue Jewish influence, Yes; “anti-Semitism,” hatred of the Jews as a people, No.” and further notes that “Had the Church really wanted to mount effective opposition to the fate that awaited the Jews, it would have had to condemn—from the very start—not only racism but anti-Semitism in any form, including the social anti-Semitism espoused by not a few churchmen. This the Church never did: not in 1933, not in 1937, nor in 1938 or 1939.”  David Kertzer interprets Pius's as meaning “Murdering Jews, burning down their homes and stores, humiliating them, these were all unchristian and inhumane. But taking “legitimate” actions to defend the rest of the population from the Jews, this was something he did not oppose.” The Popes comments were made to a group of Belgian pilgrims and were never reported in the Vatican's own newspaper but did appear in other European Catholic papers. Saul Friedländer wrote “He did not criticise the ongoing persecution of the Jews, and he included a reference to the right of self-defense (undue Jewish influence). Nonetheless his statement was clear: Christians could not condone anti-Semitism of the Nazi kind”.
In the 1939 issue of B'nai B'rith's National Jewish Monthly features him on the frontcover and writes, "Regardless of their personal beliefs, men and women everywhere who believe in democracy and the rights of man have hailed the firm and uncompromising stand of Pope Pius XI against Fascist brutality, paganism, and racial theories. In his annual Christmas message to the College of Cardinals, the great Pontiff vigorously denounced Fascism...The first international voice in the world to be raised in stern condemnation of the ghastly injustice perpetrated upon the Jewish people by brutal tyrannies was Pope Pius XI" 
Support for refugees 
Also of note is Pius XI's support for British efforts to help Jewish and other refugees...the Holy See sent out requests to its representatives throughout the world to assist those fleeing oppression and racial persecution;see Cardinal Pacelli's circular telegrams of November 30, 1938, and January 10, 1939 in Actes et Documents 6,pp. 48–50, and Pius XI's letter to the cardinal archbishops of Boston, Philadelphia, Chicago, Quebec, and Buenos Aires, pp. 50ff" 
Reaction to racial laws 
In Jan. 1939, The Jewish National Monthly reports "the only bright spot in Italy has been the Vatican, where fine humanitarian statements by the Pope have been issuing regularly". When Mussolini's anti-Semitic decrees began depriving Jews of employment in Italy, Pius XI, on his own initiative, admitted Professor Vito Volterra, a famous Italian Jewish mathematician, into the Pontifical Academy of Science.
Mit brennender Sorge 
Multiple breaches in the concordat of 1933 led the Church to forcefully condemn Nazism in the 1937 encyclical Mit brennender Sorge. This encyclical "condemned the neopaganism of the Nazi ideology – especially its theory of racial superiority". The encyclical was drafted by Cardinal Michael von Faulhaber with an introduction from the future Pope Pius XII who had previously submitted his own draft that Pius rejected for being too weak.
Nazi retaliation against the Church 
The Nazis were infuriated, and in retaliation closed and sealed all the presses that had printed it and took numerous vindictive measures against the Church, including staging a long series of immorality trials of the Catholic clergy."
According to Bokenkotter Nazi reprisals against the Church in Germany followed thereafter, including "staged prosecutions of monks for homosexuality, with the maximum of publicity". According to Catholic scholars Ehler and Morrall the initial Nazi response to the encyclical, a cry for the denunciation of the Concordant due to the Pope's interference ("but on second thoughts the Government did not do so"), the persecution of the Church lessened in subsequent years with the attitudes of both sides stabilising during the war.
This was in part influenced by the number of Catholics who now came under the orbit of German control in the wake of the Anschluss and the extension of occupied territories, leading to a Catholic population that now at least equalled that of Protestants. After the war the Concordat remained in place and the Church was restored to its previous position.
Role of Eugenio Pacelli 
When Lord Rothschild, a prominent British leader, organized a protest meeting in London against Kristallnacht, Eugenio Pacelli, Vatican secretary of state, acting on behalf of Pius XI, who was then ill, sent a statement of solidarity with the persecuted Jews; the statement was read publicly at the meeting" 
When Pius XI died on February 10, 1939 the world praised him for his opposition to the Nazi and Fascism regimes, as well as for his opposition to antisemitism.
Posthumous praise 
On Feb. 12, 1939, Bernard Joseph wrote on behalf of the Executive Jewish Agency to the Latin patriarch of Jerusalem: "'In Common with the whole of civilized humanity, the Jewish people mourns the loss of one of the greatest exponents of the cause of international peace and good will...More than once did we have occasion to be deeply grateful...for the deep concern which he expressed for the fate of the persecuted Jews of Central Europe. His noble efforts on their behalf will ensure for him for all time a warm place in the memories of the Jewish people wherever they live' 
Feb. 17, 1939, the Jewish historian Cecil Roth publishes the obituary "Pope Pius and the Jews: A Champion of Toleration" in the Jewish Chronicle of London, in which he "wrote movingly of his private audience with the aged pontiff, during which Pius XI assured Roth of the papacy's opposition to anti-Semitism. Roth hailed Pius XI as that 'courageous voice raised unfalteringly and unwearingly...protesting oppression, condemning racial madness...This was an aspect which he appreciated to the full, and earned his memory an undying claim to the gratitude of the Jewish people'" 
- Information taken from cited article on Italian Wikipedia dated 20 June 2009, retrieved 5 July 2009 
- "The Holocaust: What Was Not Said", Martin Rhonheimer, First things Magazine, November 203, Retrieved 5 July 2009 
- Popham, Peter (2003-02-21). "This Europe: Letters reveal Auschwitz victim's plea to Pope Pius XI". London: The Independent. Retrieved 2003-02-21.
- "James Carroll Takes Up a Sword Against the Church", William Doino Jr, First Things Magazine, Jun 3 2008, retrieved 12 July 2009 
- "Edith Stein's Letter", William Doino Jr, Catholic Culture 2003, retrieved 12 July 2009 
- ”Hitler, The War, and the Pope”, Ronald J. Rychlak, Our Sunday Visitor, pp. 98-99, ISBN 0-87973-217-2
- ”The Holocaust: What Was Not Said”, Martin Rhonheimer, First Things Magazine, 137 (November 2003): 18-28
- ”Unholy War”, David Kertzer, p. 280, MacMillan, 2001, ISBN 0-333-78042-6
- ”Nazi Germany and the Jews: The Years of Persecution”, Saul Friedländer, p. 251, Weidenfeld & Nicolson, 1997, ISBN 0-297-81882-1
- Chadwick, Ibid
- Pius War, p.119
- See 'Scholars at the Vatican,' Commonweal, December 4, 1942, pp.187-188)
- Vidmar, pp. 327–33l
- "The papacy, the Jews, and the Holocaust", Frank J. Coppa, p. 162-163, CUA Press, 2006, ISBN 0-8132-1449-1
- Pham, p. 45, quote: "When Pius XI was complimented on the publication, in 1937, of his encyclical denouncing Nazism, Mit Brennender Sorge, his response was to point to his Secretary of State and say bluntly, 'The credit is his.'"
- "Church and state through the centuries",Sidney Z. Ehler & John B Morrall, p. 518-519, org pub 1954, reissued 1988, Biblo & Tannen, 1988, ISBN 0-8196-0189-6
- Bokenkotter, pp. 389–392, quote "And when Hitler showed increasing belligerance toward the Church, Pius met the challenge with a decisiveness that astonished the world. His encyclical Mit Brenneder Sorge was the 'first great official public document to dare to confront and criticize Nazism' and 'one of the greatest such condemnations ever issued by the Vatican.' Smuggled into Germany, it was read from all the Catholic pulpits on Palm Sunday in March 1937. It exposed the fallacy and denounced the Nazi myth of blood and soil; it decried its neopaganism, its war of annihilation against the Church, and even described the Fuhrer himself as a 'mad prophet possessed of repulsive arrogance.'
- (Pius War, p.119).
- Quotes below from: Ibid. p.120,121
- Pinchas Lapide, Three Popes and the Jews, p.116
- Pius War, p.120-121