The Crusades lasted 200 years and represented the most extreme expression of the futile violence inherent in western feudalism – a murderous attack on the Middle East by western feudal thugs under the banner of religion.

Western feudalism created powerful armed bodies of men. In a fragmented world of rival polities, feudal rulers competed for control of land and wealth to sustain armies of armoured cavalry.

The primary role of these armies was to defend the interests of the feudal lord to whom their members owed allegiance. But the arrangement was fragile. Feudal knights had interests of their own, and the feudal system had the potential to implode into violence and anarchy.

A particular source of instability was the rule of primogeniture, by which the eldest son inherited the entire estate. Younger sons therefore faced loss of status unless they sold their military services in return for pay, booty, or new fiefs.

The system, in effect, produced surplus violence. This gave to it a powerful drive towards expansion. Either the violence was discharged in foreign war and the creation of new feudal estates, or it threatened civil war and the overthrow of existing rulers.

This was the bloody logic that led to the Crusades. The 200-year history of the Crusades represents the most extreme expression of the futile violence inherent in western feudalism.

When Pope Urban II launched the First Crusade at the Council of Clermont on 27 November 1095, he is recorded saying: ‘Let those … who are accustomed to wantonly wage private war against the faithful march upon the infidels … Let those who have long been robbers now be soldiers of Christ. Let those who once fought against brothers and relatives now rightfully fight against the barbarians. Let those who have been hirelings for a few pieces of silver now attain an eternal reward …’

The Church, with estates spread across Western Europe, was a vast feudal corporation. It competed for power and wealth with secular feudal princes. Anything that enhanced the Church’s clout – such as the wave of religious zeal and activity unleashed in 1095 – was an advantage. And, like other feudal potentates, the bishops were keen to preserve peace at home by exporting violence and instability overseas.

The response exceeded all expectations. Thousands answered the call. A great feudal army entered Syria in 1097, captured Antioch in 1098, and then entered Jerusalem in 1098.

Everywhere, there was massacre, destruction, and robbery. Men, women, and children were put to the sword as they fled in terror through the streets of captured Middle Eastern cities. Prisoners were routinely decapitated. Mosques, synagogues, and ‘heretic’ churches were ransacked. Carts were filled with plunder.

Four Crusader states were formed. The tactical dominance of feudal heavy cavalry on the battlefield had made this possible. But the Crusaders remained a tiny military elite. Just 500 knights defended the Principality of Antioch.

To survive, the Crusaders needed to invest in military power. This required intensive surplus-accumulation. The result was: a) extreme exploitation of the Arab peasantry; b) routine plundering of trade-caravans; and c) a hostile relationship with neighbouring Islamic states.

The Crusader blitzkrieg had broken through so easily because the Middle East had become divided into rival states ruled by unpopular palace-based autocrats propped up by mercenaries and largely divorced from civil society.

Many Islamic rulers sought an accommodation with the Crusaders. But no lasting peace was possible. Two contradictions were at work. First, the weakness and insecurity of the feudal settler-states made them annexationist – they needed more land to support more knights – and this was a direct threat to Islamic rulers.

Second, inside the Crusader states, the imperative of military accumulation meant heavy taxes, rents, and labour-services. Consequently, the Crusaders were hated by their Muslim subjects, and there was no possibility of raising native forces to fight in their defence.

The ‘shock and awe’ of the First Crusade broke Muslim resistance for a generation. But the Crusader threat to the rulers of the Islamic states drove a process of political centralisation.

Northern Syria and Northern Iraq were united in 1128. Then Edessa was recaptured and added to the growing Islamic state in 1144. The Second Crusade of 1146-1148, organised in response to the Islamic resurgence, was a disastrous failure. This shattered the myth of Crusader invincibility.

Damascus and Southern Syria were added to the new state, and the Crusader Principality of Antioch shrank to a small coastal enclave. Finally, in 1183, Egypt was fused with the new Syrian super-state.

The fusion of Egypt and Syria under the leadership of Saladin, a general of Turkish origin, gave the Muslim resistance critical mass. Saladin answered the feudal Crusade with a call for popular Jihad. Muslim forces went onto the offensive.

On 4 July 1187, at the Battle of Hattin, Saladin, at the head of 30,000 men, destroyed the entire army of the Crusader Kingdom of Jerusalem. The recapture of the holy city followed soon after.

Despite a series of further expeditions, the Crusaders never recovered. Though it took a century to complete the process, their castles were reduced one by one, and their territory gradually stripped away.

The Crusader states had contributed nothing to the Middle East. Their rulers were simply brutal exploiters who ruled by force and fear. They endured for so long only because of the fragmentation and decadence of the Islamic ruling class.

Their violent incursion had, however, been the catalyst of an Islamic revival, with new unities and identities forged in the struggle against the Crusader states.

The Crusades had also revealed the limits of western feudalism. Knights and castles were expensive. Super-exploitation was therefore necessary to sustain them. Despite the cost, the violence of the warrior caste constituted a permanent threat to the property and security of the common people.

The bitterness this caused could be contained by fear of feudal violence, but it could not be eradicated. Feudalism was incapable of giving rise to a stable social order based on consent.

Back home, these contradictions were contributing to the rise of new social forces inside the womb of the old order. Kings were elevating themselves above the feudal host. The central state was beating down over-mighty subjects. Gentry and yeomen – as the English called them – were rallying to the cause of royal order against baronial anarchy.

And new social forces meant new ways of war. Common men armed with pikes, bows, and guns were challenging the battlefield supremacy of feudal chivalry.