The discovery and study of other texts and the labours of recent workers have cleared up passages that offered difficulties to him, but his work will remain for a very long time the base of all investigations. The Pyramid Texts, and the older texts quoted or embodied in them, were written, like every religious funerary work in Egypt, for the benefit of the king, that is to say, to effect his glorious resurrection and to secure for him happiness in the Other World, and life everlasting. They were intended to make him become a king in the Other World as he had been a king upon earth; in other words, he was to reign over the gods, and to have control of all the powers of heaven, and to have the power to command the spirits and souls of the righteous, as his ancestors the kings of Egypt had ruled their bodies when they lived on earth. The Egyptians found that their king, who was an incarnation of the "Great God," died like other men, and they feared that, even if they succeeded in effecting his resurrection by means of the Pyramid Texts, he might die a second time in the Other World. They spared no effort and left no means untried to make him not only a "living soul" in the Tuat, or Other World, but to keep him alive there. The object of every prayer, every spell, every hymn, and every incantation contained in these Texts, was to preserve the king's life. This might be done in many ways. In the first place it was necessary to provide a daily supply of offerings, which were offered up in the funerary temple that was attached to every pyramid. The carefully selected and duly appointed priest offered these one by one, and as he presented each to the spirit of the king he uttered a formula that was believed to convert the material food into a substance possessing a spiritual character and fit to form the food of the _ka_, or "double," or "vital power," of the dead king. The offerings assisted in renewing his life, and any failure to perform this service was counted a sin against the dead king's spirit. It was also necessary to perform another set of ceremonies, the object of which was to "open the mouth" of the dead king, _i.e._ to restore to him the power to breathe, think, speak, taste, smell, and walk. At the performance of these ceremonies it was all-important to present articles of food, wearing apparel, scents and unguents, and, in short, every object that the king was likely to require in the Other World. The spirits of all these objects passed into the Other World ready for use by the spirit of the king. It follows as a matter of course that the king in the Other World needed a retinue, and a bodyguard, and a host of servants, just as he needed slaves upon earth. In primitive times a large number of slaves, both male and female, were slain when a king died, and their bodies were buried in his tomb, whilst their spirits passed into the Other World to serve the spirit of the king, just as their bodies had served his body upon earth.