|Umayyad Caliphate, c750AD|
"Tell me what to do", said the King upon his throne,
"but speak to me in whispers for we are not alone,
They tell me that Jerusalem has fallen to the hand
Of some bedevilled Eastern heathen who has seized the Holy land;"
Then the Chamberlain said "Lord, we must call upon our foes
In Spain and France and Germany to end our bitter wars,
All Christian men must be as one and gather for the fight,
You will be their leader, begin the battle cry,
Jerusalem is lost,
Jerusalem is lost,
Jerusalem is lost"...
Back when I was at school, the 'big picture' of history was mostly based around the major Mediterranean civilisations: Ancient Egypt, Greece, Rome, the Dark Ages, the Italian Renaissance, then the focus moves north for the Industrial Revolution and parliamentary democracy. There is a major omission from that list. Worryingly, even though the days when I studied history now count as history themselves, the list today would be pretty much the same.
Back in 1979, when Chris de Burgh released the song Crusader, from which the verses above were taken, it was taken for granted that crusaders were heroes, working together to free the Holy Land from heathen invaders. In recent years the pendulum has swung completely the other way: I recently heard a (geographically-challenged) preacher talking about the Crusades as an example of early European oppression of black people. Either way the picture is of civilised Europeans attacking primitive Arabs. Which displays deep ignorance, as well of a degree of probable racism.
Back at the time of the First Crusade the Muslim Empire was the superpower of the era (at least in the West). Militarily, economically, scientifically and culturally it was the overwhelmingly dominant western civilisation. From its beginnings in the Arabian Peninsula, it had swept west across the top of Africa, then turned north to invade Europe through Spain. To the east, it reached as far as India, and to the north pushed up through the Middle East and into Anatolia (Turkey, as it is now known). The trigger for the First Crusade was when the Islamic advance turned west from Anatolia heading for Europe from the east.
Guarding the south-eastern entrance to Europe was the battered remains of the old Eastern Roman Empire (at this stage pretty much reduced to Greece, Macedonia, Bulgaria and the western end of Anatolia). The rest of Europe was a patchwork of tiny barbarian states, continually fighting one another. To emphasise: at this time the Muslims were the cultured, civilised superpower, and the Europeans were the uncultured, uncivilised barbarians. As the 11th Century progressed the Islamic superpower was inexorably advancing upon Eastern Europe. Finally, in 1095, the Byzantine leader, Alexios I, called for help from Pope Urban II, in Rome.
The religious situation in Europe at the time was odd. After the assorted barbarian tribes had swept across Europe as the Roman Empire collapsed, Christian missionarise went out, against the tide, spreading the word of Jesus amongst them. Afterwards the Roman Church did the diplomacy thing amongst the leaders of the new states, with the result that pretty much all of the 11th Century European states considered themselves Christian. So when the Pope sent out the word (in suitably vague terms) that Muslim armies had invaded and taken the holy city of Jerusalem, people across the whole of Europe responded. The barbarian states sent their men, from kings to peasants, to defend 'Christendom' (and, incidentally, Europe). Then they went back to fighting one another.
Much has been made of the way the Crusader armies behaved during this time. Basically they behaved barbarically - which is not unexpected from barbarians. But this was also a time when people who had never been more than half-a-day's walk from their homes, set off on a two thousand mile journey to fight for what they believed to be right. Barbarian or no, many crusaders were heroic in their commitment. And the Crusades did successfully delay the Islamic invasion of Europe by almost 4 centuries (Constantinople finally fell in 1453). Eventually the Muslim armies of Suleiman the Magnificent reached Vienna, in 1529, but that was their high-water mark.
In summary: the First Crusade was a defensive war by European barbarians against an invading Islamic superpower, in which the Europeans behaved barbarically.