The Jewish prayer that was banned by Church

Aleinu is a prayer that marks the closing of the morning, afternoon and evening service in a synagogue. Today it is found in many Jewish prayer books, but at many points of our long and painful history it would be censored by the Church, and Jews would risk and sometimes lose their lives because of it. The Hebrew word aleinu means “it is our duty”, as in “it us our duty to praise (leshabei’ach) [G-d]”. The prayer is alternately attributed to Joshua of the Exodus fame after the conquest of Jericho or to Tanna Rav in 3rd century Babylonia who may have composed it for Rosh Hashanah services. Regardless of its origin, the prayer proved to be quite controversial wherever Jews lived among Christians. It would frequently raise ire of the Christian Church, since ecclesiastical authorities considered the prayer an insult to Christians and Jesus, even though it mentions neither.

While there’s no evidence that the prayer was composed specifically with either Christianity or Jesus in mind (indeed, the offending passage is based on Isaiah 41:29), nevertheless the Church would frequently seek to censor and excise it from Jewish prayer books. In fact, just a few days ago, on February 25th, the Jewish people commemorated the 1336 edict by the king of Castile prohibiting the recitation of the Aleinu. King Alfonso XI of Castile was prompted to this action by a Jewish convert to Christianity Abner of Burgos (who took on the name Alfonso of Valladolid upon his conversion), who convinced the king of its anti-Christian contents. Today, Aleinu has been restored to many prayer books. It is recited while standing in honor of G-d.

I recreate the Aleinu prayer in its entirety:

It is our duty to praise the Master of all things, to exalt the Creator of all existence, that He has not made us like the nations of the world, nor cause us to be like the families of the earth; that He has not assigned us a portion like theirs, nor a lot like that of all their multitudes, for they bow to vanity and nothingness. But we bend the knee, bow down, and offer praises before the supreme King of kings, the Holy One, blessed be He, who stretches forth the heavens and establishes the earth, the seat of whose glory is in the heavens above, and the abode of whose majesty is in the loftiest heights. He is our G-d, there is none else. Truly, He is our King; there is nothing besides Him, as it is written in His Torah: Know this day and take unto your heart that the L-rd is G-d; in the heavens above and upon the earth below there is nothing else. (Deuteronomy 4:39)