Then, too, the religious education of the slaves came to be recognized as a matter of great importance. Religion played an important part in the life of the Spanish colonies in general. It was therefore only natural that they should employ every available means to convert the African slave from his "false heathen superstitions" to their own "true faith." Besides, it had long been the theory of tyrants that if men were imbued with religious fervor and taught self-immolation, they were thus rendered more docile under oppression. The slave code accordingly required every master to instruct his slaves in religion. One of the first and most marked results of this encouragement of religious feeling was quite different from what had been expected or intended. That was, to arouse a strong and increasing repugnance to the legal continuance of the institution of slavery. This prevailed among the better class of owners as well as among the slaves themselves. More and more frequent became the custom of providing by will for the emancipation of slaves at the death of their masters. The natural affection, also, to which we have referred, which arose between slaves who acted as domestic or body servants and the owners who enjoyed such faithful service, conduced to the same end. The natural inclination of the humane master was to grant such servitors their freedom. Despite these palliating circumstances, slavery was odious, and persistent negro insurrections began to cause serious concern to the white population. In hope of checking them by kindness, new laws were enacted. Legal restrictions were placed upon the hours of labor. It was decreed that except under certain stated conditions a master should not work his slaves more than nine or ten hours a day. When the exigencies of the season required greater efforts, sixteen hours were prescribed as the extreme limit, and the master was required to give extra pay for the extra time. But these regulations were difficult if not impossible to enforce. Indeed, we must assume that they were not meant to be enforced. They were for show and nothing more; and they remained practically a dead letter. Religious scruples could not and of course did not prevent the performance of much labor on Sundays, and the needs of agriculture often made work necessary on holidays. There were routine duties to be performed every day. For these, two hours were regarded as sufficient, and to such time the code restricted the labor of Sundays and holidays. There was also a general provision under which slaves were granted the right to labor on their own account, paying a certain part of their wages to the masters and retaining the remainder from which they might, if they desired, create a fund looking toward their own eventual freedom.