The reciprocal obligations of the vassal and his suzerain were numerous, some moral, some material. The vassal was bound to loyally preserve the secrets confided to him by his suzerain (Fig. 13), to prevent and frustrate any treachery on the part of his enemies, to defend him at the risk of his own life, to resign his own horse on the battle-field should his lord have lost his, to go as a prisoner in his stead, to cause his honour to be respected, and to assist him with his advice. At the simple request of the suzerain, the vassal was bound to follow him to the field, either alone or accompanied with a specified number of armed men, according to the importance of the fief. The duration of this military service varied, in like manner, in proportion to the fief, from twenty to sixty days--a period that did not admit of very distant expeditions. The feudal seignior stood in place of the sovereign, and being invested with executive authority, had necessarily, in order to exercise it, recourse to the latent force distributed amongst his vassals, and he naturally did so in accordance with his own convenience. Justice, administered in this manner, was termed _fiance_, that is to say, public security. The seignior was wont to summon the men of his fief or fiefs to his _plaids_, or assizes, either for the purpose of assisting him with their advice, to act with him as judges, or to carry out the sentences he pronounced. He had a right to two kinds of assistance--obligatory, or _legal aids_, and voluntary, or _gracious aids_. Legal aids were due from the vassal under three sets of circumstances: when the seignior was taken prisoner and had to pay a ransom, when his eldest son was about to be made a knight, and when he gave away his eldest daughter in marriage. In feudal society these aids stood in the place of the public taxes, which in ancient times, as in our own days, were collected by the State alone; they differed, however, in this respect, that they were not due at any stated periods, nor perhaps could they ever be absolutely enforced, they were a kind of voluntary gift--from the bestowal of which, however, few vassals dared to free themselves. [Illustration: Fig. 11.--Act of Faith and Homage, Twelfth Century.--Seal of Conon de Béthune, preserved in the National Archives of France.] [Illustration: Fig. 12.--Act of Faith and Homage, Thirteenth Century.--Seal representing Raimond de Mont-Dragon kneeling before the Archbishop of Arles, his Suzerain, in the National Archives of France.]