The military service required of a vassal was generally limited to forty days in a year. If more was needed, the king must pay all expenses. If the military service was to be rendered in a foreign country, the noble was free to come home at the end of forty days. He must also help the king by his advice, and must submit in any lawsuit of his own to the decision of the king and his fellow vassals, and he must provide entertainment for the king when on a journey. On three occasions he was expected to assist the king with money, but this was never called payment or rent for land, it was always spoken of as "aid." These occasions were: 1. When the king's eldest son was made a knight; 2. When the king's eldest daughter was married; 3. When the king had been taken prisoner by some foreign power and it was necessary to ransom him.

In theory, the king had a right to take back the grant of land; but unless a vassal was unfaithful, it was seldom to his advantage to do so. If one vassal was wronged by another, he might appeal to their king; but it was in most cases a long way to the royal court, it was dangerous to leave one's castle exposed to an enemy, and it was more simple and direct for the two nobles to fight it out. If a vassal died, it was generally for the gain of both parties that his eldest son should take the father's place as vassal. The lord imposed a tax, however, called "heriot," usually the best beast of the dead man. The son, too, was required to pay a tax, or "relief," on taking possession of the land in his father's stead. The accepted belief was that every fief should supply to the king the service of a man. If the vassal's son was a child at his father's death, the king brought him up; but to make good the loss of a fighting man, he kept the income of the fief until the boy was old enough to perform a knight's service. If the vassal left only a widow or a daughter, she must pay a fine to the king if she did not wish to marry. If she was willing to marry, the king had the right to select her husband. This was to prevent her from choosing a man who might perhaps be an enemy to the king.

This was the "feudal system," or rather it was the beginning of it. It is quite probable that in many countries, at some time in their history, land has been held by this method. Of course it was not decided upon and the land divided in a moment in any country, but the custom grew up gradually. The system was in reality a perfect network of lords and vassals, for not only were the nobles vassals of the king, but they themselves had vassals, and those vassals had others who had paid homage to them. Indeed, a man might do homage to a number of men for separate pieces of land. In that case, however, he owed military duty to but one of them, and this one was known as his "liege" lord. The vassal was not looked upon as in any degree inferior to the lord. A king might rule one country and yet pay homage to the ruler of another for his fief in that land. When William the Norman conquered England, he took possession of the country much as if it had been his own big farm. He allowed those who yielded to him to retain their land on payment of large fees. The rest of it he divided among his followers as fiefs. But William was Duke of Normandy, and therefore he himself paid homage to the French king for his Norman land. This descended from one English ruler to another; but when John came to the throne, the French king, Philip II, declared that he was a disobedient and unfaithful vassal, and took it away by capturing the Château Gaillard and his other strongholds.

There were several ways in which smaller amounts of land came into the hands of the nobles. The Church held large areas; but the clergy were forbidden to wield the sword, therefore parts of their holdings were sometimes let to knights on condition of their providing the required number of soldiers. Again, this was a time of fighting and bloodshed, of danger and violence; and many a man who owned a bit of freehold could not protect it. In that case he would often "commend" himself to some powerful man; that is, he would promise to be faithful to him and be his loyal vassal. He now had a strong arm to defend him, and he was sure of food and clothes. The result of all this was that by the thirteenth century it might almost be said, "No land without a lord."

But manors were of small value unless they were cultivated. In these days, if a man owns a large farm, he hires laborers to work on it; but in the Middle Ages the cultivation of the land was managed in quite a different fashion. Nothing has been said as yet of the "common folk," the many thousand people who were neither clergy nor nobles. They were the ones who did the work of the manors. They were of various ranks. A few were slaves, and were looked upon as having no more rights than a horse or a cow. Above these were the villeins. They could not be sold like slaves, but if a manor passed from one lord to another, they went with it. Each villein held a definite amount of land, and was required to pay for its use partly in money or in produce and partly in labor. The villeins were divided into several classes, each having some special rights or some exemption from undesirable duties which was of great value to them. Above these were the free tenants. They paid for the use of their land, sometimes in service and sometimes entirely in money.

The buildings on a manor were the manor house, in which either the lord or his agent lived; the tiny cottages of the tenants; a church; a windmill; and the various barns and other outbuildings needed. The manor house stood a little apart from the others. It was usually of stone, but its character depended in great degree upon the location. In England, for instance, the important houses near the Scottish border were built strong enough to serve as forts; and, indeed, most of the larger houses in the more level parts of the country were surrounded by moats and had various means of defense. In the simpler houses there was a hall, and adjoining it a kitchen. On the other side of the hall and up a flight of stairs was the "solar." This was the bedroom and parlor of the lord and his wife. The rest of the household and their guests slept in the hall or in the stables or in any other place where they would be under a roof, even one thatched with reeds from the pond. As time passed, houses were built with more rooms, often enough to enclose a courtyard on three sides, while the fourth was shut in by a wall. Around the whole structure was a moat with a drawbridge. The windows were small, there were turrets and other places from which arrows might be shot in safety; in short, these manor houses were in many respects almost as well fortified as real castles. The cottages were ranged along the one street of the manor, miserable little one-room sheds of clay, the roofs thatched with straw stubble and having neither windows nor chimneys.