Pope Benedict XIV (1751) issued an encyclical arguing for the ghettoization of Polish Jews because of their numbers and their effects on the Catholic comunities.
In addition to the harm done to Christians in these regards, other unreasonable matters can result in even greater loss and danger. The most serious is that some households of the great have employed a Jew as "Superintendent-of-the-Household"; in this capacity, they not only administer domestic and economic matters, but they also ceaselessly exhibit and flaunt authority over the Christians they are living with. It is now even commonplace for Christians and Jews to intermingle anywhere. But what is even less comprehensible is that Jews fearlessly keep Christians of both sexes in their houses as their domestics, bound to their service. Furthermore, by means of their particular practice of commerce, they amass a great store of money and then by an exorbitant rate of interest utterly destroy the wealth and inheritance of Christians. Even if they borrow money from Christians at heavy and undue interest with their synagogues as surety, it is obvious to anyone who thinks about it that they do so to employ the money borrowed from Christians in their commercial dealings; this enables them to make enough profit to pay the agreed interest and simultaneously increase their own store. At the same time, they gain as many defenders of their synagogues and themselves as they have creditors. (Papal Encyclical, On Christians and Jews living in the same place: A Quo Primum, 14 June 1751).