In support of the fighting man

At the heart of feudalism is a basic idea common to any society with a warrior caste. Such men need to be provided for. In a simple economy this means that the produce of an appropriate number of peasants or serfs must underwrite the expenses of the fighting man. In ancient Sparta, where all free men are warriors, the support comes from the defeated and enslaved peasants of Messenia, known as the helots.

In medieval Europe the system is more complex. The central economic feature is the Manorial system. Transcending that, and dependent upon it, is the interconnecting network of loyalties and obligations which make up feudalism.

Lord and vassal: 8th - 12th century AD

The feudal system comes into focus during the 8th century, when the Carolingian dynasty is expanding its territory. Charles Martel grants his nobles rights over tracts of land, to yield the income with which they can provide fighting men for his army. This act of generosity, ultimately for his own benefit, requires an oath of loyalty in return.

Thus there develops the relationship between lord and vassal which is at the heart of feudalism. The lord gives the vassal an income-yielding fief (fehu-od in Frankish, the basis of the word 'feudal'). The vassal does homage to the lord, formalizing the relationship.

The largest fiefs are those given directly by monarchs to noblemen or barons, who then subcontract parts of these fiefs to vassals of their own. Only in this way, sharing out both the benefit and the obligation, can the king's vassals be sure of bringing their promised contingent of armed men into the field.

A pyramid of loyalty is thus created, in which each man - except at the very top and bottom - is a vassal to one lord and a lord to several vassals. At the very peak of European feudal society is the pope. By the end of the 12th century the Papacy has more feudal vassals than any temporal ruler.

Feudal Europe: 10th - 15th century

Although Feudalism develops as early as the 8th century, under the Carolingian dynasty, it does not prevail widely in Europe until the 10th century - by which time virtually the entire continent is Christian.

For the next 500 years, great accumulations of power and landed wealth pass between a few favoured players as if in a vast board game. The rules are complex, and to an outside eye deeply mysterious. But certain actions and qualifications bring a distinct advantage.

The top players in feudal Europe come from a small group of people - an aristocracy, based on skill in battle, with a shared commitment to a form of Christianity (at once power-hungry and idealistic) in which the pope in Rome has special powers as God's representative on earth. As a great feudal lord with moral pretensions, holding the ring between secular sovereigns, the pope can be seen as Europe's headmaster.

Bishops and abbots are part of the small feudal aristocracy, for they are mostly recruited from the noble families holding the great fiefs. Indeed bishops can often be found on the battlefield, fighting it out with with the best.

As in any other context, the strongest argument in Feudalism - transcending the niceties of loyalty - is naked force. The Normans in England or in Sicily rule by right of conquest, and feudal disputes are regularly resolved in battle.

But Feudalism also provides many varieties of justification for force. And the possession of a good justification is almost as reassuring to a knight as a good suit of armour.

One excellent excuse for warfare is the approval of the church. In 1059 the pope virtually commands the Normans to attack Sicily, by giving them feudal rights over territory not as yet theirs. Similarly Rome lets it be known that the Holy See is on the side of William when he invades England in 1066.

Another important form of justification is a dynastic claim to a territory. Generations of marriages, carefully arranged for material gain, result in an immensely complex web of relationships - reflected often in kingdoms of very surprising shape on the map of Europe.

A simple example is the vast swathe of land ruled over in the 12th century by England. Stretching from Northumberland to the south of France, it has been brought together by a process of inheritance and dynastic marriage.

More complex, but equally typical of Christian Feudalism, is the case of Sicily. In the 11th century the Normans seize it by invitation of the pope. In the 12th century the island is joined to distant Germany because the German king marries a Sicilian princess. And in the 13th century it is linked with France because the pope, intervening again, is now opposed to the Germans.

Complexity and decline: 12th - 15th century AD

With the passage of time the feudal system becomes more complex, more rigid, more open to abuse. Fiefs tend to become hereditary, reducing the personal link between vassal and lord. Payments of money begin to replace the original simple obligation of armed service. Religious institutions - monasteries, abbeys, bishoprics - take their place in the hierarchy, providing administrative and sometimes even military support for their feudal lords, while growing prosperous through the efficient administration of their manors.

The original feudalism, a structure of personal relationships, tends in one direction towards centralized monarchy - and in another towards anarchy.

In some regions kings successfully use the feudal hierarchy to reinforce their own position at the top of the pyramid. This happens in England (where William I starts with a clean slate, distributing conquered territory on his own terms to his followers) and in France (where the Capetian house has the accidental benefit of a long unbroken succession of direct male inheritance).

By contrast in Germany, where the elected German king proves unable to assert strong authority over his elective peers, the feudal pyramid declines into a discordant group of independent fiefs - some held by noble families, some by religious institutions, and a few by the burghers of the developing towns.

The weaknesses in European feudalism are evident by the 13th century, but the system of interconnecting feudal obligations remains a central theme in Europe until at least the 15th century.

Thereafter the strong authority of kings, taxing and ruling from a central base, becomes for a while the norm in European government. But feudal customs and rights remain enshrined in the law of many regions (including France, Germany, Austria and Italy) until abolished either by the French revolution or by the reforms of Napoleon.