of the mantras are "themselves sacred," and "do not constitute linguistic utterances." Instead, as Klostermaier notes, in their application in Vedic rituals they become magical sounds, "means to an end." Holdrege notes that there are scarce commentaries on the meaning of the mantras, in contrast to the number of commentaries on the Brahmanas and Upanishads, but states that the lack of emphasis on the "discursive meaning does not necessarily imply that they are meaningless." In the Brahmanical perspective, the sounds have their own meaning, mantras are considered as "primordial rhythms of creation", preceding the forms to which they refer. By reciting them the cosmos is regenerated, "by enlivening and nourishing the forms of creation at their base. As long as the purity of the sounds is preserved, the recitation of the mantras will be efficacious, irrespective of whether their discursive meaning is understood by human beings." Frazier further notes that "later Vedic texts sought deeper understanding of the reasons the rituals worked," which indicates that the Brahmin communities considered study to be a "process of understanding." A literary tradition is traceable in post-Vedic times, after the rise of Buddhism in the Maurya period, perhaps earliest in the Kanva recension of the Yajurveda about the 1st century BCE; however oral tradition of transmission remained active. Jack Goody has argued for an earlier literary tradition, concluding that the Vedas bear hallmarks of a literate culture along with oral transmission, but Goody's views have been strongly criticised by Falk, Lopez Jr,. and Staal, though they have also found some support. The Vedas were written down only after 500 BCE, but only the orally transmitted texts are regarded as authoritative, given the emphasis on the exact pronunciation of the sounds. Witzel suggests that attempts to write down the Vedic texts towards the end of 1st millennium BCE were unsuccessful, resulting in smriti rules explicitly forbidding the writing down of the Vedas. Due to the ephemeral nature of the manuscript material (birch bark or palm leaves), surviving manuscripts rarely surpass an age of a few hundred years. The Sampurnanand Sanskrit University has a Rigveda manuscript from the 14th century; however, there are a number of older Veda manuscripts in Nepal that are dated from the 11th century onwards. Vedic learning The Vedas, Vedic rituals and its ancillary sciences called the Vedangas, were part of the curriculum at ancient universities such as at Taxila, Nalanda and