The 9th century came to define the great number of Zoroastrian texts that were composed or re-written during the 8th to 10th centuries (excluding copying and lesser amendments, which continued for some time thereafter). All of these works are in the Middle Persian dialect of that period (free of Arabic words), and written in the difficult Pahlavi script (hence the adoption of the term "Pahlavi" as the name of the variant of the language, and of the genre, of those Zoroastrian books). If read aloud, these books would still have been intelligible to the laity. Many of these texts are responses to the tribulations of the time, and all of them include exhortations to stand fast in their religious beliefs. Some, such as the "Denkard", are doctrinal defenses of the religion, while others are explanations of theological aspects (such as the Bundahishn's) or practical aspects (e.g., explanation of rituals) of it.