Avesta as "Fragments Tahmuras"; and the "Hadokht Nask" "volume of the scriptures" with two fragments of eschatological significance. Only texts preserved in the Avestan language count as scripture and are part of the Avesta. Several other secondary works are nonetheless crucial to Zoroastrian theology and scholarship. The most notable among the Middle Persian texts are the "Dēnkard" ("Acts of Religion"), dating from the ninth century; the "Bundahishn" ("Primordial Creation"), finished in the eleventh or twelfth century, but containing older material; the "Mainog-i-Khirad" ("Spirit of Wisdom"), a religious conference on questions of faith; and the "Book of Arda Viraf", which is especially
Religion with solemnity and gravity. The sociologist Émile Durkheim, in his seminal book "The Elementary Forms of the Religious Life", defined religion as a "unified system of beliefs and practices relative to sacred things". By sacred things he meant things "set apart and forbidden—beliefs and practices which unite into one single moral community called a Church, all those who adhere to them". Sacred things are not, however, limited to gods or spirits. On the contrary, a sacred thing can be "a rock, a tree, a spring, a pebble, a piece of wood, a house, in a word, anything can be sacred".