The Diet of Mainz (older: Diet of Mayence) was a meeting of the Estates General of the Holy Roman Empire

Holy Roman Empire

The Holy Roman Empire was a realm that existed from 962 to 1806 in Central Europe.It was ruled by the Holy Roman Emperor. Its character changed during the Middle Ages and the Early Modern period, when the power of the emperor gradually weakened in favour of the princes...

 held in Mainz in 1188. It led to the Third Crusade

Third Crusade

The Third Crusade , also known as the Kings' Crusade, was an attempt by European leaders to reconquer the Holy Land from Saladin...

.

Saladin

Saladin

Ṣalāḥ ad-Dīn Yūsuf ibn Ayyūb , better known in the Western world as Saladin, was an Arabized Kurdish Muslim, who became the first Sultan of Egypt and Syria, and founded the Ayyubid dynasty. He led Muslim and Arab opposition to the Franks and other European Crusaders in the Levant...

 had captured Jerusalem from the Christians in the autumn of 1187. At the instigation of Frederick I, Holy Roman Emperor

Frederick I, Holy Roman Emperor

Frederick I Barbarossa was a German Holy Roman Emperor. He was elected King of Germany at Frankfurt on 4 March 1152 and crowned in Aachen on 9 March, crowned King of Italy in Pavia in 1155, and finally crowned Roman Emperor by Pope Adrian IV, on 18 June 1155, and two years later in 1157 the term...

, who was now 68 years old but was an ardent Christian, the "Court Day of Jesus Christ" took place on the 27th of March, at Easter, 1188. The purpose of the gathering was to organize a Third Crusade

Third Crusade

The Third Crusade , also known as the Kings' Crusade, was an attempt by European leaders to reconquer the Holy Land from Saladin...

.

Quotations

"After the capture of Jerusalem by Saladin, the Christians of the East, in their distress, sent to the West their most eloquent prelate and gravest historian William, Archbishop of Tyre, who, fifteen years before, in the reign of Baldwin IV., had been Chancellor of the kingdom of Jerusalem. He, accompanied by a legate of Pope Gregory VIII., scoured Italy, France, and Germany, recounting everywhere the miseries of the Holy Land, and imploring the aid of all Christian princes and peoples, whatever might be their own position of affairs and their own quarrels in Europe. At a parliament assembled at Gisors, on the 21st of January, 1188, and at a diet convoked at Mayence on the 27th of March following, he so powerfully affected the knighthood of France, England, and Germany, that the three sovereigns of these three states, Philip Augustus, Richard Coeur de Lion, and Frederick Barbarossa, engaged with acclamation in a new crusade."
[Pope] "Gregory VIII. had meanwhile died after a pontificate of less than two months; but an enthusiastic summons

Audita tremendi

Audita tremendi was a papal bull issued by Pope Gregory VIII on October 29, 1187, calling for the Third Crusade.It was issued just days after Gregory had succeeded Urban III as pope, in response to the defeat of the Kingdom of Jerusalem at the Battle of Hattin on July 4 of 1187...

to the crusade which he had composed before his death was read at Mayence. Here, in the midst of a scene of wild excitement, the emperor and his son, Frederick of Suabia, took the cross. Following the example of their gray-haired sovereign thousands of knights assumed the votive emblem."

Threats to the Jews

At the time of the reports of the fall of Jerusalem, many Jews of the Rhineland, reacting to Christian death threats, fled to safety in castles nearby.

Defence of the Jews

A "courageous handful" remained behind during the Diet of Mainz to petition the Emperor directly. Frederick, who was known as friendly to Jews, and the local authorities took measures during this period to prevent anti-Jewish crimes, including actively repelling a "full-scale invasion of the Jewish neighborhood" of Mainz.