The obligations of the vassal varied greatly.[69] Sometimes homage meant no more than that the vassal bound himself not to attack or injure his lord in honor or estate, or oppose his interests in any other manner. The vassal was expected to join his lord when there was a military expedition on foot, although it was generally the case that the vassal need not serve at his own expense for more than forty days. The rules, too, in regard to the length of time during which a vassal might be called upon to guard the castle of his lord varied almost infinitely. The shorter periods of military service proved very inconvenient to the lord. Consequently it became common in the thirteenth century for the king and the more important nobles to secure a body of soldiers upon whom they could rely at any time, and for any length of time, by creating money fiefs. A certain income was granted to a knight upon condition that the grantee should not only become a vassal of the lord but should also agree to fight for him whenever it was necessary. [Sidenote: Other feudal obligations.] [Sidenote: Money payments.] Besides the military service due from the vassal to his lord, he was expected to attend the lord's court when summoned. There he sat with other vassals to hear and pronounce upon those cases in which his peers--i.e., his fellow-vassals--were involved.[70] Moreover, he had to give the lord the benefit of his counsel when required, and attend him upon solemn occasions. Under certain circumstances vassals had to make money payments to their lord, as well as serve him in person; as, for instance, when the fief changed hands through the death of the lord or of the vassal, when the fief was alienated, when the lord was put to extra expense by the necessity of knighting his eldest son or providing a dowry for his daughter, or when he was in captivity and was held for a ransom. Lastly, the vassal might have to entertain his lord should the lord come his way. There are amusingly detailed accounts, in some of the feudal contracts, of exactly how often the lord might come, how many followers he might bring, and what he should have to eat. [Illustration: A Mediæval Castle near Klagenfurt, Austria] [Sidenote: Different classes of fiefs.] There were fiefs of all kinds and of all grades of importance, from that of a duke or count, who held directly of the king and exercised the powers of a practically independent prince, down to the holding of the simple knight, whose bit of land, cultivated by peasants or serfs, was barely sufficient to enable him to support himself and provide the horse upon which he rode to perform his military service for his lord. [Sidenote: The nobility.] [Sidenote: Their privileges.]