Here is an interesting history of the Crusades, what they were, what precipitated them, etc. Although I have posted the entire section due to the copyright stipulation at the bottom, I have bolded the section that is relevent to this thread. I believe that it clarifies the basic difference between Islam and other religions or religious systems. I don't see that much has changed over the centuries regarding the ideology that political control of the world is the goal of the Faithful of Islam. I believe that they mistakenly believe that this is their mandate from Allah. I think that explains why all the terrorism currently going on in countries all over the globe is being perpetrated by adherents of Islam. I don't believe that "radical" Islam is destroying Islam. I believe that Islam's basic ideology of world political control is the problem, and they have not changed their stripes since their beginnings. Yes, there are moderate Muslims (mostly westernized Muslims who are considered infidels by the Faithful) who occasionally speak out against the atrocities committed by the "radicals", but by and large, there is a deafening silence from the Muslim world, as LoveBug stated.
You can check out the link below this chapter to read additional chapters.
I also think that anyone seriously interested in understanding current world affairs should read the Koran.
ORB Online Encyclopedia
Political and Military Background
To begin to answer the question, "What were the Crusades?" one must first consider the history of Europe and the Middle East in the millenium before 1095.
Beginning in the first century A.D., the religion known as Christianity arose in Palestine and spread rapidly throughout the Roman Empire. By the end of the fourth century, the Roman Empire had become officially and primarily Christian, as a result of peaceful missionary activity from within society (later church, or canon, law in fact forbade forced conversions). Jerusalem, Palestine and Syria, all within the boundaries of the Roman Empire, became predominantly Christian (the Jewish population of Jerusalem had been largely dispersed by pagan Roman authorities following the Jewish anti-Roman revolts of A.D. 66-70 and 132-135, and few Jews remained in the area).
In the seventh century A.D., the religion known as Islam arose in the Arabian peninsula. Like Christianity, Islam officially condemned forced conversions. But unlike Christianity, Islam instructed its followers to ensure that the world was under the political control of the Faithful. Hence Islam's political domination could be, and was, spread by the sword.
Carried on the backs of Arab cavalry, Islam burst out of Arabia and quickly took control of the Middle East. Byzantium and Persia, the two powers in the area, were exhausted by prolonged conflict with each other. Persia was completely defeated and absorbed into the Islamic world. The Middle Eastern armies of the Christian Byzantine Empire were defeated and annihilated in 636, and Jerusalem fell in 638. Through the rest of the seventh century, Arab armies advanced inexorably northwards and westwards.
By the early eighth century Arab forces had reached the Straits of Gibraltar, and in 711 they crossed into European Spain and shattered the armies of the Christian Visigoths. By 712 they had reached the center of the Iberian Peninsula, and by the 730s they were raiding deep into the heart of France, where Charles Martel met and defeated their most ambitious raid near Tours around 732. This was to prove their high water mark in the West.
For the next 300 years Christians and Muslims engaged in a protracted struggle, including the siege of Constantinople by the Arabs in 717-18, and the seizure of Sicily and other Mediterranean islands in the ninth century by the Muslims. In the tenth century the Byzantines made some limited gains along the periphery of the now-shrunken Empire, but did not retake Jerusalem.
In the middle of the eleventh century the Arabs were displaced as leaders of Islam by the Turks, who converted to Islam even as they conquered the Arabs. The Turks disrupted the area's political and social structures and created considerable hardships for Western pilgrims. Up till now most Arab rulers of the area had been fairly tolerant of Christian interest in the Holy Places (one notable exception was the "Mad" Caliph Hakim at the beginning of the eleventh century, who destroyed churches and persecuted Jews and Christians). By the second half of the eleventh century, most pilgrims were going to the Holy Land only in large, armed bands, groups who look in retrospect very like crusade rehearsals.
The Turks also posed a new threat to the Byzantines. In 1071 the Turks met and crushed the Byzantine army at the Battle of Manzikert, near Armenia. As a result the entire heartland of the Empire, in Asia Minor, lay open and defenseless, and the Turks soon established themselves as far west as Nicaea, just across the Bosphorus from Constantinople. In the same year the Normans in southern Italy, led by Robert Guiscard, defeated the Byzantines at Bari and drove them off the Italian mainland.
The Imperial Byzantine crown was briefly contested following Manzikert and Bari; the successful claimant was Alexius Comnenus, a capable soldier and a clever diplomat. Perceiving that the Empire was deprived of its primary recruiting grounds and breadbasket, he sent out desperate calls for help to the West, particularly to the pope. Gregory VII briefly considered leading an expedition eastwards himself in support of the Byzantines. However, he was too preoccupied both by the Investiture Controversy with the Holy Roman Emperor Henry IV, and by the growth of Norman power under Robert Guiscard in southern Italy, to respond in any meaningful way.
Alexius continued to appeal to the West, however, and in the spring of 1095 Pope Urban II allowed Byzantine delegates to address the Council of Piacenza, and he gave his sanction to those nobles who were inclined to respond. He then proceeded into France, attending to various church business. By November he was in Clermont, and it was here that he gave a speech which caught the imagination of the West.
It is hard to know exactly what Urban had in mind when he called for expeditions to the East. We have various texts of his speech; none agree exactly, but it seems unlikely that Urban envisaged waves of Frankish peasants travelling to Jerusalem. Alexius had called for large contingents of mercenaries, particularly Normans, to come and take service in the Byzantine Army. Urban probably had something a little more elaborate than that in mind--among other things, he probably hoped that an expedition to the East, carried out under papal leadership and comprised of noblemen from across western Europe, would boost his position in the ongoing Investiture Controversy with the Holy Roman Empire.
Military and Political Background
The First Crusade
Crusades and the Counter-Crusades
The Later Crusades
Crusading Vows & Privileges
Copyright (C) 1997, Paul Crawford. This file may be copied on the condition that the entire contents,including the header and this copyright notice, remain intact.