Alexios I Komnenos, Emperor of the Byzantine Empire, called upon Western European Christians to help him defeat the Seljuk Turks in what eventually became the First Crusade.
Hardly, it was the Byzantine Church who appealed to the pope for help.
At the request of the Byzantine Emperor Alexius Comnenus, Pope Urban II called for knights from western Europe to come and help the Byzantines drive the Seljuk Turks out of Palestine.
Pope Urban II granted the Byzantine emperor help against the Seljuk Turks in order to liberate churches of God in eastern regions. Pope Urban II passed away before receiving news of the fall of Jerusalem.
Pope Urban II (1088-1099) called for the Christians to defeat the Turks. This is known as the first crusade and the war for the liberation of the Holy Land.
the Crusades originally had the goal of recapturing Jerusalem and the Holy Land from Muslim rule and their campaigns were launched in response to a call from the Christian Byzantine Empire for help against the expansion of the Muslim Seljuk Turks into Anatolia.
The Seljuks were not actually that important to Palestine. They conquered the territory and administered it until the Crusader States removed their control. The Seljuks did not build any impressive structures in Palestine, move any important populations into or out of Palestine, or help to define any Palestinian national identity.
Dermot McMurrough invited them, to help him regain his throne in Ireland. They came in the year 1169.
No one
The eastern part of the Roman empire fell in 1453 to the Ottoman Turks who took Constantinople. Prior to this the Eastern Roman Empire had gradually been loosing territory to successive invaders: the Arabs had taken the Middle East south of Turkey and Egypt, the Bulgars, Serbs and Croats had taken the Balkans and the Seljuk Turks had taken a big chunk of Turkey. The Ottoman Turks took over form the Seljuk Turks, completed the conquest of Turkey and dealt the final blow.
The crusaders defeated the Turks at the city of Jerusalem.
Yes - all the Commonwealth countries helped defeat Germany
The french