Cum nimis absurdum was a papal bull issued by Pope Paul IV dated 14 July 1555.

Considering that the Church of Rome tolerates these very Jews evidence of the true Christian faith and to this end [we declare]: that they, won over by the piety and kindness of the See, should at long last recognize their erroneous ways, and should lose no time in seeing the true light of the catholic faith, and thus to agree that while they persist in their errors, realizing that they are slaves because of their deeds, whereas Christians have been freed through our Lord God Jesus Christ, and that it is iniquitous for it to appear that the sons of free women serve the sons of maids.The bull revoked all the rights of the Jewish community and placed religious and economic restrictions on Jews in the Papal States, renewed anti-Jewish legislation and subjected Jews to various degradations and restrictions on their personal freedom.

Gian Pietro Carafa was seventy-nine when he assumed the papacy as Pope Paul IV, and was by all accounts austere, rigidly orthodox, and authoritarian in manner.

[3] Deutsch and Jacobs link this to part of the reaction to the Protestant Reformation that led to censorship of books deemed detrimental to Christians.

[4] According to Herbert Thurston, "[E]dicts issued at various times for the destruction of copies of the Talmud, the Bull 'Cum nimis absurdum' of Paul IV constraining the Jews of Rome to live segregated in a Ghetto and subject to other harassing disabilities, represent ... the prejudices of individual pontiffs ..."[6] There was to be no more than one synagogue in each state, territory and domain.

[5] These restrictions contradicted a precedent set as early as 598, by Gregory I which clearly laid down that the Jews were to be allowed to keep their own festivals and religious practices, and their rights of property, even in the case of their synagogues.

At the expiration of the specified number of months, if Jews sold a security deposit, they were to remit all money in excess of the principal of the loan to the owner of the collateral.

[8] Serena di Nepi argues that "in spite of the increasing implosion of the Jewish world of Rome, imposed by papal policy, which imposed exclusion and enclosure, the Jews of Rome were able to hold steadfast to an identity, preserve a specificity and defend themselves against persisting attempts to convert them through active proselytism and social exclusion calculated to erode their adherence to their Jewish faith.