Would've been nice if the papal bulls had been real bulls that would charge down anyone who tried to hurt Jews...
If only
There's an old saying attributed to Stalin: “
How many divisions does the Pope of Rome have?”
In his brutal humour, Stalin's joke was of course about the fact that no matter how powerful a pontiff may be (in theory i.e. infallible, supreme pontiff of the church akin to a High Priest), in practice he doesn't directly commandeer a vast Soviet-style military empire like he did, papal pretensions aside.
So, while some popes - indeed a good number who reiterated the Gregorian Charter
Sicut Judaeis from the 12th till the 15th century - tried to safeguard legal protections for Jewish communities and condemn the anti-Semitic blood libel, they would have had varying degrees of success in actually achieving that, despite their theoretical plenitude of power.
But so far as the canon law was concerned, on paper, this was the official policy, even though in practice it would have been enforced to the extent able and anti-semitism was, of course, sadly widespread in medieval society. Again from the Jewish Virtual Library (great website by the way):
Here's the form in which Pope Gregory X articulated the Sicut Judaeis in 1272:
Papal Protection of the Jews
"Gregory, bishop, servant of the servants of God, extends greetings and the apostolic benediction to the beloved sons in Christ, the faithful Christians, to those here now and to those in the future...
We decree moreover that no Christian shall compel them [Jews] or any one of their group to come to baptism unwillingly. But if any one of them shall take refuge of his own accord with Christians, because of conviction, then, after his intention will have been manifest, he shall be made a Christian without any intrigue. For, indeed, that person who is known to have come to Christian baptism not freely, but unwillingly, is not believed to posses the Christian faith.
Moreover no Christian shall presume to seize, imprison, wound, torture, mutilate, kill or inflict violence on them; furthermore no one shall presume, except by judicial action of the authorities of the country, to change the good customs in the land where they live for the purpose of taking their money or goods from them or from others.
In addition, no one shall disturb them in any way during the celebration of their festivals, whether by day or by night, with clubs or stones or anything else. Also no one shall exact any compulsory service of them unless it be that which they have been accustomed to render in previous times.
Inasmuch as the Jews are not able to bear witness against the Christians, we decree furthermore that the testimony of Christians against Jews shall not be valid unless there is among these Christians some Jew who is there for the purpose of offering testimony.
Since it happens occasionally that some Christians lose their children, the Jews are accused by their enemies of secretly carrying off and killing these same Christian children and of making sacrifices of the heart and blood of these very children. It happens, too, that the parents of these very children, or some other Christian enemies of these Jews, secretly hide these very children in order that they may be able to injure these Jews, and in order that they may be able to extort from them a certain amount of money by redeeming them from their straits.
And most falsely do these Christians claim that the Jews have secretly and furtively carried away these children and killed them, and that the Jews offer sacrifices from the heart and the blood of these children, since their law in this matter precisely and expressly forbids Jews to sacrifice, eat, or drink the blood, or to eat the flesh of animals having claws. This has been demonstrated many times at our court by Jews converted to the Christian faith: nevertheless very many Jews are often seized and detained unjustly because of this...
We decree, therefore, that Christians need not be obeyed against Jews in a case or situation of this type, and we order that Jews seized under such a silly pretext be freed from imprisonment, and that they shall not be arrested henceforth on such a miserable pretext, unlesswhich we do not believethey be caught in the commission of the crime. We decree that no Christian shall stir up anything new against them, but that they should be maintained in that status and position in which they were in the time of our predecessors, from antiquity till now.
We decree in order to stop the wickedness and avarice of bad men, that no one shall dare to devastate or to destroy a cemetery of the Jews or to dig up human bodies for the sake of getting money. Moreover, if any one, after having known the content of this decree, should which we hope will not happen attempt audaciously to act contrary to it, then let him suffer punishment in his rank and position, or let him be punished by the penalty of excommunication, unless he makes amends for his boldness by proper recompense."