- The Avesta
The chief source for the teachings of Zarathushtra (known to the West as Zoroaster) is the compilation of holy works called the Avesta, a name which probably means The Injunction (of Zarathushtra)'. The Avesta is composed in two stages of an otherwise unrecorded Eastern Iranian language: 'Gathic' Avestan (GAv.), which in its forms is close to the language of the Indian Rigveda (which is generally assigned to the second millennium B.C.); and 'Younger' Avestan (YAv.). Gathic Avestan takes its name from the chief texts to survive in this dialect, i.e. the seventeen Gathas composed by the prophet himself. Although only this part of the Avesta is directly attributable to him, traditionally the whole Avesta is held to be inspired by his teachings; and many Younger Avestan texts are presented as if directly revealed to him by God. When Zarathushtra lived the Iranians were not familiar with writing; and for many centuries afterwards they regarded this alien art as fit only for secular purposes. All their religious works were handed down orally; it was not until probably the fifth century A.C. that they were at last committed to writing, in the 'Avestan' alphabet, especially invented for the purpose. The oldest extant ms. is dated to 1323 A.C.

- The Gathas
The word 'gatha' (which exists also in Sanskrit) is variously rendered as 'hymn', 'poem', or 'psalm'. Zarathushtra's Gathas are short verse texts, cast largely in the form of utterances addressed by him to Ahura Mazda; and they convey, through inspired poetry, visions of God and his purposes, and prophecies of things to come, here and hereafter. They are full of passionate feeling and conviction, with meaning densely packed into subtle and allusive words; and in form they belong, it seems, to an ancient and learned tradition of religious poetry composed by priestly seers, who sought through study and meditation to reach direct communion with the divine. However, they are the only examples of this tradition to survive in Iran; and this literary isolation, together with their great antiquity, means that they contain many words of unknown or uncertain meaning, and have baffling complexities of grammar and syntax. All this, added to their depth and originality of thought, makes them extraordinarily difficult to translate. Only a few verses can be understood by themselves in a wholly unambiguous way; but keys to their interpretation are provided by the Younger Avesta and the Pahlavi Zand (see below), which set out clearly doctrines often only alluded to in the Gathas. Linguistically the Rigveda, being composed in a closely related sister language of comparable antiquity, provides great help. The living tradition of the faith, especially in worship, is also an invaluable aid.

- The Gathic portion of the Yasna
The Gathas were piously preserved by being made part of the liturgy of the Yasna (Y.), the 'Act of worship', which was solemnised daily. They were arranged formally in five groups, according to their five metres, and were set before and after the Yasna Haptanhaiti (YHapt.), the 'Worship of the seven Sections'. This, also in Gathic Avestan, appears to be made up of what are in essence even more ancient texts, composed to accompany the traditional offerings to fire and water, and revised in the light of Zarathushtra's teachings. So in Zoroastrian worship the Gathas, as the greatest of manthras (inspired holy utterances) guard the central rituals of the faith with their sacred power. Before and after them the four great prayers are recited, brief but very holy utterances which are constantly being said.

- The Younger Avestan portions of the Yasna
The Yasna liturgy was extended over the centuries, and finally grew to have seventy-two sections. These, almost all in Younger Avestan, are of varying age and content. The Gathic texts were kept at the heart of the liturgy, being now protected in their turn by the Younger Avestan additions.

- The Yashts
Some of the materials of the extended Yasna were taken from the Yashts (Yt.), hymns to the lesser divine beings of Zoroastrianism. A few of these are known as the 'great yashts', because of their length, and the poetic quality and antiquity of some of their verses, which (as Rigvedic parallels show) go back in substance to the Indo-Iranian period i.e. to at least 2000 B.C.; but even such ancient materials survive in the Younger Avestan dialect, since only the Gathic texts were exactly memorised, because of their great holiness. Other, less sacred, works were handed down in a more fluid oral transmission, that is, partly memorised, partly composed afresh by each generation of poet-priests, so that the language in which they were recited evolved with the spoken tongue. New matter was also added, so that these too are composite works, with explicitly Zoroastrian doctrines closely interwoven with older traditional matter, and with later materials.

- The Vendidad
The Vendidad (Vd.) is a mixed collection of prose texts in late Younger Avestan, probably compiled in the Parthian period. Most are concerned with the purity laws, as a means of combating the forces of evil; and its name, a corruption of Av. Vidaevadata, means 'Against the Daevas' i.e. the evil beings. At some stage, probably during the early Islamic period, it was made part of a night celebration of the Yasna, being read aloud then in its entirety. Even today this is the only liturgical text which is not recited entirely from memory.

- The Visperad
This long liturgy consists of an extended Yasna with Vendidad, the extensions being mainly additional invocations. Its name means the '(Worship of) All the Masters'; and it was solemnised especially on the seven great holy days of the faith (see 1.6).

- The Nyayesh and Gah
The five Nyayesh (Ny.) are prayers for regular recitation by priests and laity alike. They are addressed to the Sun and Mithra (to be recited together, three times a day); the Moon (three times a month); the Waters and Fire. They again are composite works and contain verses from the Gathas and Yashts, as well as later material. The five Gah are texts of similar character. They are meant to form part of the prayers to be recited during each of the five divisions (gah) of the twenty-four hours, and contain invocations of the lesser divinities who watch over each of these periods (cf. 2.3.3.21).

- The Khorda or Little Avesta
This name is given to selections from the above texts which, together with some Middle Persian ones, form a book of common prayer. Every Khorda Avesta contains the same body of essential prayers for everyday use, but there is some variation in their arrangement, and in the selections from the Yashts. Some have at the end a few prayers in a modern language (Persian or Gujarati). The laity have used Khorda Avestas only since the nineteenth century A.C. (when the holy texts were first printed); before then they learnt all their prayers by heart from the family priest or their parents.


- The 'Great' Avesta
Under the Sasanians a canon of Avestan texts was established, grouped into twenty-one nasks (books); and it was this massive collection of holy texts which was at last committed to writing in the fifth or sixth century A.C. This 'Great' Avesta contained all the texts already described, and much else, including the life and legends of the prophet, expositions of doctrine, apocalyptic works, and books of law, cosmogony, and scholastic science. Copies were presumably placed in the libraries of the chief fire temples; but during the Islamic period these fire temples were all destroyed, through successive conquests by Arabs, Turks and Mongols, and not a single copy of the Great Avesta survives. The scope of its contexts is, however, known from a detailed summary given in a Pahlavi book, the Denkard (see below); and from this it appears that the extant Avestan texts amount to about a quarter of the whole canon. They survived because they were in constant devotional use, and so were both known by heart and set down in mss. which were frequently recopied by priests in their own homes.

- Avesta fragments
Some fragments of Avestan texts survive. They include portions of the Hadhokht Nask, which appears to have been used at one time liturgically; and parts of two very cryptic and difficult works on priestly rituals, the Nirangistan and Herbadistan.

- The Pahlavi Zand
Zand or 'Interpretation' is a term for the exegesis of Avestan texts through glosses, commentaries and translations. There existed of old a Zand in the Avestan language itself, whose glosses are sometimes incorporated in the original texts; and there would have been Zands in the various languages of the diverse Iranian peoples down to the fourth century A.C. Thereafter the Sasanians, the last Zoroastrian dynasty to rule Iran, imposed their own language, Middle Persian or Pahlavi, generally. The Middle Persian Zand is therefore the only one to survive fully, and it is regarded accordingly as 'the' Zand. Middle Persian has a grammar which is so simple that it can produce ambiguities; and it is written in a difficult script, with too few letters for clarity, and the use of fossilised Aramaic ideograms. Its study therefore presents its own difficulties.

- The Zand of extant Avestan texts
Almost all extant Avestan texts, except the Yashts, have their Zand, which in some mss. is written together with the Avesta. The two were often spoken of in one phrase, as Zand-Avesta, so that at first Western scholars took Zand to be a synonym for Avesta, or to refer to the language in which the holy texts are written. Where the Avesta and Zand coexist, it can be seen how priestly scholars first translated the Avestan as literally as possible, then often gave a more idiomatic Middle Persian translation, and finally added explanations and commentaries, often of ever-increasing length, sometimes with differing authorities being cited.

- The Zand of lost Avestan texts
Several important Pahlavi books consist largely or in part of selections from the Zand of lost Avestan nasks, often cited by name; and by comparing these with the Zand of extant texts it becomes possible to distinguish fairly confidently the translation from the paraphrases and commentaries, and so to attain knowledge of missing doctrinal and narrative Avestan works. Among these Pahlavi books is the Bundahishn (Bd.), 'Creation', which deals not only with creation and its purposes, but also with the nature of the divine beings, and with eschatology. It exists in two recensions, known as the Iranian or Greater (because longer) Bundahishn, and the Indian Bundahishn. It has the subtitle Zand-Agahih, 'Knowledge from the Zand'. Wizidagiha, 'Selections' (from the Zand), were compiled by a leading Persian priest, Zadspram, in the ninth century A.C. (WZ.), and include materials for the life of the prophet, which existed in more than one Avestan nask. More details of his life, also taken from the Zand, are contained in the Denkard (Dk.). This, the 'Acts of the Religion', is a massive compilation of very diverse materials, made in the ninth and tenth centuries A.C. This was a period of considerable literary activity by Zoroastrian priests, in the face of the growing threat posed by Islam; but much of the matter which they then re-edited for the enlightenment of their community was very ancient in substance.

- Other anonymous Pahlavi works
Much Pahlavi literature remains essentially an oral literature committed to writing, which retains many of the characteristics of oral composition. Thus most Pahlavi works are anonymous, and successive redactors felt free to add to them at will, or to rehandle them for their own purposes. It is usually impossible, therefore, to date such works effectively, since their contents may range from the very ancient to matter contemporary with the last redactor.

- Pahlavi works of known authorship
A few Pahlavi works by named individuals survive, composed between the sixth and tenth centuries A.C. All, being preserved by priestly copyists, are concerned in some way with religion.

- Persian Zoroastrian writings
After the tenth century even Zoroastrians abandoned composition in Pahlavi almost entirely for modern Persian, written in Arabic script with many Arabic loan words. Gradually the community was reduced by persecution to a poor and intellectually isolated minority, whose energies had to go into surviving and into preserving the core of the teachings of their faith. The Persian Zoroastrian writings, whether in prose or verse, consist therefore mainly of re-renderings of older materials.

- Sanskrit, Old Gujarati and Pazand writings
In the ninth century A.C. a band of Zoroastrians left Iran to find religious freedom in Gujarat, western India, where they were known as Parsis, i.e. Persians. They adopted Gujarati as their mother tongue, and in the late eleventh or early twelfth century some of their scholar priests began translating Avestan texts from the Middle Persian Zand into Sanskrit and Old Gujarati. Some other Pahlavi texts were also translated, or were transcribed into the clear Avestan alphabet. The latter process, being a form of interpretation, was known as 'pa-zand\ Pazand texts, transcribed phonetically, represent a late and often corrupt Middle Persian pronunciation, and so present their own problems.

-The Persian Rivayats
From the fifteenth to the eighteenth centuries Irani and Parsi priests corresponded sporadically on matters of ritual and observance. The Iranis' answers to Parsi questions are preserved as the 'Persian Rivayats', and shed valuable light on the religious life of the community, and especially on the operation of the far-reaching purity laws.

- Modern literature
From the mid-nineteenth century, when the Parsis were prospering greatly, there is a considerable Parsi literature, in Gujarati and English, concerned with doctrines and observances. Down to this period the Zoroastrian tradition appears highly conservative and orthodox; but the community suffered severe mental and emotional shocks through the abruptness of its encounter with the world of modern thought; many of its devout members were left confused and troubled, and began to look hurriedly for new interpretations of ancient doctrines and rituals. Many Parsi devotional works, from this time onward, are unconsciously influenced therefore by Christian, Hindu or theosophical teachings, and some reformist ones incline to a simple theism, with virtually no observances. From the twentieth century there is a smaller body of corresponding Persian writings by Iranis, in which some unconscious Muslim influence is also apparent. In the nineteenth and twentieth centuries Parsi priests began to write detailed expositions of the rituals and ceremonies of the faith, in Gujarati and English. The Pahlavi ritual texts are too technical and concise to be readily understood, and so these more recent works are valuable for the light they shed on Zoroastrian worship. This is the more important since Parsis do not admit non-Zoroastrians to their holy places.

Secular records

- Records of the Achaemenian period (c.550-330B.C
Towards the end of the second millennium B.C. the Iranian tribes moved south off the steppes, and gradually conquered and settled the land now called, after them, Iran. Eastern Iranians evidently carried Zoroastrianism with them, and eventually the western Iranians, i.e. the Medes and Persians, also adopted the faith. It became the religion of the Persian Achaemenians, whose empire (see map) was the greatest in the ancient world; and religious material occurs in their inscriptions. The Avesta itself remained, however, Eastern Iranian in substance as well as language, and there is no reference in it to these or any other Western Iranians, although the Medo-Persian magi became the best known of the Zoroastrian priests.
There are also a number of notices of the 'Persian religion' by Greek writers at this period, and after Alexander's conquest of the Achaemenian empire. This conquest appears to have done much harm to the transmission of Avestan texts, through the slaughter of priests.

- Records of the Parthian period (c. 141 B.C.-224 A.C
The Arsacids, coming from north-east Iran, established the second Iranian empire, that of the Parthians. Their scanty written records show that they too upheld the Zoroastrian faith. There are Greek and Latin references to Zoroastrian observances at this time, and traces survive in Pahlavi literature of the Parthian transmission of religious texts. A long Parthian courtly romance, 'Vis u Ramin', contains interesting Zoroastrian material.

- Records of the Sasanian period (c. 224-651 A.C
The second Persian empire, that of the Sasanians, is the epoch from which Zoroastrianism as an imperial faith is best known. The early kings, and their high priest, Kirder, left inscriptions; and in the fifth century Persian priests began to compile an immense chronicle, the 'Book of Kings' (MP. Khwaday Namag, NP. Shahname), whose early sections linked the Sasanian dynasty artificially with Vishtaspa, Zarathushtra's royal patron. This chronicle survives only through Arabic translations and the great Persian epic version of it by Firdausi, finished c. 1000 A.C. A number of other Sasanian works which contain some Zoroastrian matter are known only through Arabic or NP. renderings.

- Notices by Muslim writers
After the overthrow of the Sasanian empire by the Muslim Arabs a number of notices of Zoroastrians occur in Muslim histories and geographies. These are most numerous in the ninth and tenth centuries, and cease with the Mongol conquest of Iran in the thirteenth century, after which the Irani Zoroastrians become too insignificant in numbers and status to be further regarded.

- Early Parsi records
In 1599 a Parsi priest completed a poem in Persian, the 'Qissa-i Şanjan'. Celebrating the history of the oldest Parsi sacred fire, it is based mainly on early oral traditions of the Parsis. From this time on Parsi records of various kinds (inscriptions, legal documents, genealogies, etc.) increase steadily.

- Notices by European merchants and travellers
In the seventeenth and eighteenth centuries European merchants and travellers encountered Zoroastrians in Iran and India and wrote reports of them.

- Modern Parsi and European writings
In the nineteenth century individual lay Parsis published descriptions of the traditional beliefs and practices of their co-religionists; and in this and the following century European scholars did the same for the very similar ones of the older Irani communities. These accounts make it possible to compare traditional Zoroastrianism, as it was lived down to and into modern times, with the growing diversity of beliefs and practices which has been developing since the nineteenth century.

Source
Textual Sources for the Study of Zoroastrianism by Mary Boyce