The last two books are manifestly late additions. Book XIX. consists of a mixture of supplementary pieces, part of the text of which is rather corrupt. Book XX., with a slight exception, contains only complete hymns addressed to Indra, which are borrowed directly and without any variation from the Rigveda. The fact that its readings are identical with those of the Rigveda would alone suffice to show that it is of later date than the original books, the readings of which show considerable divergences from those of the older Veda. There is, however, more convincing proof of the lateness of this book. Its matter relates to the Soma ritual, and is entirely foreign to the spirit of the Atharva-veda. It was undoubtedly added to establish the claim of the Atharva to the position of a fourth Veda, by bringing it into connection with the recognised sacrificial ceremonial of the three old Vedas. This book, again, as well as the nineteenth, is not noticed in the Pratiçakhya of the Atharva-veda. Both of them must, therefore, have been added after that work was composed. Excepting two prose pieces (48 and 49) the only original part of Book XX. is the so-called kuntapa hymns (127-136). These are allied to the danastutis of the Rigveda, those panegyrics of liberal kings or sacrificers which were the forerunners of epic narratives in praise of warlike princes and heroes. The existence of the Atharva, as a collection of some kind, when the last books of the Çatapatha Brahmana (xi., xiii., xiv.), the Taittiriya Brahmana, and the Chhandogya Upanishad were composed, is proved by the references to it in those works. In Patanjali's Mahabhashya the Atharva had already attained to such an assured position that it is even cited at the head of the Vedas, and occasionally as their only representative.