world. We may say, however, that they fall into two classes, general and specific. The general included all that might come under the idea of loyalty, seeking the lord's interests, keeping his secrets, betraying the plans of his enemies, protecting his family, etc. The specific services are capable of more definite statement, and they usually received exact definition in custom and sometimes in written documents. The most characteristic of these was the military service, which included appearance in the field on summons with a certain force, often armed in a specified way, and remaining a specified length of time. It often included also the duty of guarding the lord's castle, and of holding one's own castle subject to the plans of the lord for the defence of his fief....

"Theoretically regarded, feudalism covered Europe with a network of these fiefs, rising in graded ranks one above the other from the smallest, the knight's fee, at the bottom, to the king at