Gregory IX’s legacy is difficult to separate from the institutions and campaigns he supported, especially where religious authority was used to punish dissent and suppress Jewish learning.

Gregory IX established the Papal Inquisition, which became an institution defined by moral certainty, coercion, and a willingness to punish the accused whether they were guilty or innocent. In that sense, it echoed the Roman practice of targeting those accused of failing to worship in the approved way.

In 1239, after a public disputation between Christians and Jewish theologians, Gregory ordered all copies of the Jewish Talmud to be confiscated. The order culminated in the mass burning of roughly 12,000 handwritten Talmudic manuscripts. I have always wondered how early Christian leaders could so easily condemn the very people from whom Jesus came.

A Jewish man whose life inspired a religion that has endured for 2,000 years would surely have frowned on the persecution of his people. And for anyone who forgets the obvious: Jesus was not a Christian.

That fact matters, because it exposes a deep contradiction in later Christian persecution of Jewish communities.

The central figure of Christianity was not condemned as the leader of a new religion. He was tried and executed as a political troublemaker, a rabble-rouser whose message unsettled those in power.

Gregory IX also endorsed the Northern Crusades and supported efforts to bring Orthodox Slavic peoples in Eastern Europe under papal authority, where persuasion too often arrived at the edge of a sword.