Was that the one who, with his wife, converted to Catholicism after the War, drawn in some part at least by how impressed he was with how much Pius XII had done to help the Jews?
You are right Mary. The Chief Rabbi of Rome converted to Catholicism - in part because of his gratitude for what Pius had done for the Jews. Which was - save 800,000+ of them from execution.
On February 28, 1945, the Chief Rabbi of Jerusalem, Isaac Herzog, sent a letter of gratitude to the Apostolic Nuncio in Romania (a Msgr. Andrea Cassulo) stating that:
The people of Israel will never forget what His Holiness and his illustrious delegates, inspired by the eternal principles of religion which form the very foundations of civilization, are doing for us unfortunate brothers and sisters in the most tragic hour of our history, which is living prove of divine Providence in this world.
Israeli senior diplomat and scholar Pinchas Lapide, with access to the Yad Vashem (the Holocaust Martyrs' and Heroes' Remembrance authority) archives has proved that
The Catholic Church relief and rescue program under the pontificate of Pius XII was instrumental in saving the lives of as many as 860,000 Jews from certain death at Nazis hands. That was more than all other Churches, religious institutions and international rescue organizations put together..
The Israelis recognized the lives saved by Pius by planting a commemorative forest in the Negeb, SE of Jerusalem. 860,000 trees, one per person saved. And at Pius's funeral one of the dignitaries (might have been Golda Meir, I'm not sure) said something like
Pius, if we ever forget your kindness to us, may the sun go cold
I hope a Freeper will supply the correct quote. This whole "Pius was Hitler's Pope" nonsense is just another left-wing smear.