One of the main reasons I became interested in this era of history (which actually encompassed a number of eras) was because, even with my limited knowledge at the time, the story was seemingly always told as beginning with the first Crusade. There was never any account of the "pre-history" of the Crusades.
The motivation of the crusaders was described as that of conquest and that of expansion of influence of the Roman Catholic Church. There was no history given of the lands sought to be "overrun" by these armies who took the Cross.
After 9/11, there was much punditry concerning President Bush's use of the term "crusade" as being inappropriate or offensive, and that got me thinking. I did know that Mohammed was the father of Islam who died sometime in the 7th century and the sphere of influence of Islam at the time of his death was limited to the Arabian peninsula (essentially Saudi Arabia today and where Mecca and Medina, the holy cities of Islam are to be found). So sometime from the death of Mohammed to the 11th century Islam spread beyond its initial borders both west and east. The logical question that then came to my mind was...who were the peoples who inhabited those areas and what was their dominant faith. These were questions that could not be answered if the "history" of the Crusades were recounted only from the late-11th century forward.
The first point that is seldom mentioned, perhaps out of ignorance or perhaps out of political correctness, is that the Crusades were defensive wars in large measure the response to Muslim aggression. At the time of Mohammed, Christianity was the faith of the Roman Empire and, as such, extended throughout the Mediterranean which included the Middle East. Indeed, the Middle East was the birth place of Christianity.
After Mohammed's death his followers advanced by military might into Palestine, Syria and Egypt, all of which at the time were heavily Christian. By the next century, Muslim armies had conquered most of North Africa and Spain...again, heavily Christian areas. By the 11th century what is now modern Turkey, which had been Christian since Biblical times, fell to the Muslim armies as did most of the Byzantine empire.
It was at this point in time, after nearly four centuries of Muslim conquests which had taken over nearly two-thirds of the old Christian world that the emperor of Constantinople sent a call for help to western Europe's Christians.
Part II to follow...