In his tenure as Pope, John Paul II revolutionized Catholic-Jewish relations. It is safe to say that more change for the better took place in his 27-year papacy than in the nearly 2,000 years before.

The Pope did this by the way he wrote and spoke about the evil of anti-Semitism. He did this by visiting the Rome synagogue, the first Pope to do so. He did it by the opening 10 years ago of full relations with the State of Israel and then capped it off with his historic visit to Israel, including a moving stop at the Western wall. He did it by issuing a report on the Holocaust and by raising questions of Christian responsibility. And in some ways most important, he rejected the destructive concept of supersessionism, the word describing the delegitimization of Judaism, which had been superseded by Christianity. This historic delegitimization of Israel, based on the Jewish rejection of Jesus, became the basis of the millennia-old demonization of the Jewish people and the concomitant anti-Semitism. Now, said the Pope, Judaism is recognized as a sister religion of Christianity with intrinsic and eternal value of its own.

The significance of this combination of activities cannot be overestimated. Let us remember that Karol Wojtyla became Pope at a critical moment in Catholic-Jewish relations. The 1960s had witnessed the historic Vatican II Council statement called Nostra Aetate, which rejected two millennia of doctrine holding Jews responsible for the death of Jesus. What was unclear by 1978, with the election of a new Pope, was whether the Church would truly take the initiative of Vatican II and translate it into a radical reformulation of Catholic-Jewish relations or whether it would become a statement that, while important, never had a major impact on the Catholic world.

Into this uncertainty came John Paul II. He understood that Nostra Aetate was a vital turning point. But it needed underpinning by addressing the psychological pain and historic mistrust of the Catholic Church that pervaded the Jewish community. He understood that a variety of approaches were necessary to begin to overcome centuries of anguish.

Symbolism was critical. The images of the Pope entering the synagogue in Rome spoke volumes. His decision not only to visit Israel and not only to visit the Western Wall, the holiest spot of the Jewish people, but to place a message in the Wall, a custom that Jews all over engage in, showed the sensitivity to Jewish mores.

Speaking to Jewish insecurity was also critical. His denouncing anti-Semitism as a “sin against God and humanity” made clear that no more was this poison acceptable.

His talk of Judaism as a sister religion of Christianity gave hope that the old bases for Christian persecution of Jews no longer had the support of the Vatican.

He recognized as well that the debasement of Jews by the Church through the centuries required statements and decisions showing respect for Jews and Judaism. That, among other reasons, was why the diplomatic recognition of the state of Israel was so important.

And he knew that doctrine was critical in changing the dynamic, the most important being to give for the first time recognition to Judaism, not only as the forbearer of Christianity but as a continuing living truth that exists alongside the Christian religion.

This remarkable revolution from the top of the Catholic Church does not mean that all problems are resolved, far from it. Issues arise all the time, whether it is the baptized Jewish children during World War II who were never returned to their Jewish roots, or the beatification of Pope Pius XII, or Vatican positions on Israeli policy.

But because of the vision, because of the understanding of the suffering associated with Catholic doctrine toward Jews, that the Pope possessed, the prism through which problems are seen is completely different.

For all of us who appreciate the Pope’s contributions the challenge is to make sure that his vision will continue to resonate and to deepen. That would be the best tribute to this exceptional religious leader.

Mr. Foxman is national director of the Anti-Defamation League. He had eight audiences with the Pope, most recently in December 2004. Mr. Foxman was saved from the Holocaust by his Polish nanny who had him baptized and raised as a Catholic until his parents reclaimed him at the end of the war.