What is known to modern scholars as the Avesta is, however, only a portion of the original work, the latter having been largely lost through the conquests over Persia of Alexander the Great, and especially owing to the more thorough subjugation of the Sassanid Persians by the Muslims in A.D. 632. The latter were much more bigoted and uncompromising in their treatment of other religions and their literatures than were Alexander the Great and his successors. The original Avesta, as described in Pahlavi text which have come down to us, contain twenty-one Nasks or books. These existed, in a more or less incomplete state, down to the ninth century of our era, to which century the Pahlavi work "Dindard" belongs. The Avesta which exists to-day may be divided thus:-- I. The strictly canonical parts, including the following, which will be more fully described in connection with the summaries. 1. Yasnas, including the Gathas. 2. Vispereds. 3. Vendidads. II. The Apocryphal Avesta usually called the Khorda Avesta, or the short Avesta. This is much less esteemed than the Avesta proper. It comprises, 1. Yashts (invocation). 2. Minor Prayers. The language of the Avesta can be correctly described only as Avestan, for no other literature in the same language exists. It resembles the Pahlavi, or Ancient Persian, but it is identical with no language. The Zend, or commentary, is written in the Pahlavi language. The present writer wishes to express his obligation to the translation of the Avesta by Spiegel (in German); Hang in his "Essays on Sacred Language, Writing, and Religion of the Parsees "; and also to those by Darmesteter and L.H. Mills in the "Sacred Books of the East," volumes iv, xxiii, xxxiii. On the question whether or not the Achaemenian kings of Persia, Cyrus I., and so forth, were Zarathustrians, see "Century Bible,"--Ezra--Nehemiah--Esther. _I.--YASNAS, OR SACRIFICIAL PRAYERS AND SONGS_ [This section of the Avesta constitutes the principal liturgical text-book of the great Yasna ceremony, which is made up chiefly of the preparation and offering of the Parahoma (the juice of the homa or soma plant mixed with milk and aromatic ingredients). There are seventy-two chapters in the Yasnas, though they contain a good number of repetitions. It is in this main part of the Avesta that the five metrical Gathas are to be found, these being the oldest and by far the most important of the Avesta.]