There may well have been a Jewish preacher in the first century CE called something like Yeshu, later known as Jesus Christ, whose life formed the basis of the myths related in the Christian Gospels. If there was, then it is unlikely that he was antisemitic.
There may well have been a person called Matthew who wrote the Gospel of that name a few decades later and who has since become known as Saint Matthew. Whoever wrote that Gospel probably intended to appeal to antisemitism in his readers when he wrote of the Jews cursing their own descendants with the guilt of deicide:
His blood be upon us, and upon our children.
But whether Matthew intended it or not, the overwhelming majority of Christians throughout the ages never doubted that the Gospel story, especially the story of the death of Jesus, is virulently antisemitic and that this was right and proper.
In the early nineteenth century, a German nun called Anne Catherine Emmerich claimed to have witnessed the death of Jesus and the preceding events via a series of miraculous visions, which were written down in a book called The Dolorous Passion of Our Lord Jesus Christ. This absurd claim was believed by most Catholics and remains recognised by the Catholic Church to this day.
Emmerich was of course obsessed by The Jews and their guilt. Among the things she saw in her visions was the eternal torture of all Jews, for which she blamed only – The Jews:
Whenever, during my meditations on the Passion of our Lord, I imagine I hear that frightful cry of the Jews, ‘His blood be upon us, and upon our children,’ visions of a wonderful and terrible description display before my eyes at the same moment the effect of that solemn curse. I fancy I see a gloomy sky covered with clouds, of the colour of blood, from which issue fiery swords and darts, lowering over the vociferating multitude; and this curse, which they have entailed upon themselves, appears to me to penetrate even to the very marrow of their bones,— even to the unborn infants. They appear to me encompassed on all sides by darkness; the words they utter take, in my eyes, the form of black flames, which recoil upon them, penetrating the bodies of some, and only playing around others.
In the early twenty-first century, an actor called Mel Gibson read Emmerich's book and was inspired to produce a Passion Play (if you're not aware of the history of Passion Plays, please read this), in the form of a movie, based on Emmerich's visions.
Pope John-Paul II saw the movie and allegedly authenticated it, saying ‘it is as it was’. Since John-Paul no more has the supernatural ability to witness historical events than Emmerich or anyone else, this was taken as a moral endorsement of the content of the movie. Later, the Vatican denied the endorsement and the quotation.
Now John-Paul has beatified Anne Catherine Emmerich. Beatification is the step just short of sainthood, and is often followed by it.
What are the attributes of a saint?