It is not just his famous prayer that gives such poignancy to the High Holyday liturgy, but the tragic story that gave rise to it.
Persistently urged by the local church dignitary to become a Christian, the rabbi finally said in irritation that he would think about it.
He regretted his words at once because they implied that he might be open to persuasion, and when he was pressed for a decision and defiantly refused to convert, he was punished with unbearable torture.
Dying from his wounds, he was carried to the synagogue on Rosh HaShanah and asked the cantor to pause as he sanctified the name of God in the words which became Un’tanneh Tokef.
The scholars question certain aspects of the story, but Jewish tradition has taken it to its heart.
Rabbi Amnon was only one of many Jewish martyrs in Mayence. Known also as Mogontiacum, Moguntia and Mainz, the city is located near the confluence of the Rhine and Main rivers. From there the Romans embarked upon the conquest of the Germanic tribes, and Jews followed in their wake as soldiers and traders.
The Kalonymos family made the city a centre of rabbinic learning in the middle ages; it is said that Charlemagne brought the first Kalonymos to Mayence as its rabbi in the 9th century.
An even more famous figure was Rabbenu Gershom of Mayence, “the light of the exile”.
His edicts include the prohibition of polygamy, the general rule that a woman is not to be divorced against her will, a ban on opening other people’s correspondence, and a lenient attitude towards Jews who had been compelled to apostasise.
The Jewish history of Mayence saw many ebbs and flows. There were times when Jews were welcomed, and times when they were persecuted and banished.
There were unbelievable horrors during the Crusades. A church council in Mayence in 1233 excommunicated any Christian who associated with Jews; in 1259 Mayence Jews were forced to wear the Jewish badge. This was bad enough, but before long there came the ritual murder accusation, and by the end of the 13th century the Jews of the town decided to emigrate to the Holy Land. When the Black Death came the Judengasse was set on fire.
No wonder that by the beginning of the 16th century only one Jewish family remained.
The French Revolution brought better times for the Jews of Mayence, who were no longer restricted to a ghetto. But then came the Nazi period and even worse ferocity than that of the middle ages.
Mayence is not unique in its story, but Rabbi Amnon, and one of the Kalonymos family who transcribed his prayer, gave it a permanent place of honour in the prayer book.