Runciman's story is surely one of the most dramatic and important in the saga of Western Civilization.
Here, in brief, is the core of the story.
In February of 638 A.D., Muslim Caliph Omar entered Jerusalem, supplanting Christian Patriarch Sophronius. All the towns and cities had fallen to the Muslims. The city had been under siege for a year, but upon its surrender, Omar was careful to say that Christians had nothing to fear, as long as they didn't attempt an insurrection against their new rulers.
The Prophet Muhammad had ordered that the Christians and Jews could keep the Church of the Holy Sepulcher and other holy places.
The fall of Jerusalem was a shock to Western Christendom.
For the next 400 years, Christians watched helplessly as the Muslims consolidated their control of the Middle East. Some Westerners still attempted pilgrimages to the Holy Land. A few succeeded. While there, the local Christians begged the pilgrims to ask other westerners to come and rescue them.
The Western anger grew until in 1095 Pope Urban II in a stirring oration at the Council of Clermont called for a Holy Crusade to recapture Jerusalem.
To encourage those present, Urban offered Crusaders remission of all sins, and he guaranteed their property would be protected while they were away.
Crusade mania swept the West. Thousands rushed forward to offer their arms and fortunes to the cause.
Many of them were powerful noblemen or second sons who would inherit no land because of primogeniture.
Furthermore, the population was growing, and the working conditions of the peasants were worsening. Many of them considered the Crusade as an opportunity to improve their lives.
Another key factor contributing to the mania was the belief that the second coming of Christ was at hand. Crusaders wanted to be present when he arrived.
Urban insisted all the Crusaders gather at Constantinople. Emperor Alexius Comnenus agreed at first to play host to the Christian warriors until it became apparent their numbers would be enormous.
What would he do if he was unable to feed them before pushing them on toward the Holy Land? All of the West, along with barbarian tribes, seemed to be moving East.
Alexis gathered enormous food supplies and sent some of them ahead so the hordes would quickly pass through Constantinople and continue toward the Holy Land. It worked, and the Crusaders, after many hardships and casualties, arrived before Jerusalem and captured it.
All the while, while studying Runciman's work, I couldn't help but compare our present hostile relations with Muslims in Iraq, Iran and Pakistan.
The past is often prologue to the future.
Charlie Langdon is the Herald's senior critic. He can be reached at langdons@gobainstorm.net.