About the time of the Christian era or perhaps rather earlier, greater use began to be made of writing for religious purposes. The old practice of reciting the scriptures was not discontinued but no objection was made to preserving and reading them in written copies. According to tradition, the Pali scriptures were committed to writing in Ceylon during the reign of Vaṭṭagâmaṇi, that is according to the most recent chronology about 20 B.C., and Kanishka caused to be engraved on copper plates the commentaries composed by the council which he summoned. In Aśvaghosha[123] we find the story of a Brahman who casually taking up a book to pass the time lights on a copy of the Sutra of the Twelve Causes and is converted. But though the Buddhists remained on the whole true to the old view that the important thing was to understand and disseminate the substance of the Master's teaching and not merely to preserve the text as if it were a sacred formula, still we see growing up in Mahayanist works ideas about the sanctity and efficacy of scripture which are foreign to the Pali Canon. Many sutras (for instance the Diamond Cutter) extol themselves as all-sufficient for salvation: the Prajñâ-pâramitâ commences with a salutation addressed not as usual to the Buddha but to the work itself, as if it were a deity, and Hodgson states that the Buddhists of Nepal worship their nine sacred books. Nor was the idea excluded that certain words, especially formulæ or spells called Dhâraṇî, have in themselves a mysterious efficacy and potency.[124] Some of these are cited and recommended in the Lotus.[125] In so far as the repetition of sacred words or spells is regarded as an integral part of the religious life, the doctrine has no warrant in the earlier teaching. It obviously becomes more and more prominent in later works. But the idea itself is old, for it is clearly the same that produced a belief in the Brahmanic mantras, particularly the mantras of the Atharva Veda, and early Buddhism did not reject mantras in their proper place. Thus[126] the deities present themselves to the Buddha and offer to teach him a formula which will protect his disciples from the attacks of evil spirits. Hsüan Chuang even states that the council which sat at Râjagṛiha after the Buddha's death compiled five Pitakas, one of which consisted of Dhâraṇîs,[127] and it may be that the collection of such texts was begun as early as the collection of discourses and rules. But for many centuries there is no evidence that they were in any way confounded with the Dharma.