Avesta word for "praise-song" (Bartholomae: "Lobgesang"); that word is not actually attested in any text. The surviving texts of the Avesta, as they exist today, derive from a single master copy produced by Sasanian Empire-era (224–651 CE) collation and recension. That master copy, now lost, is known as the 'Sassanian archetype'. The oldest surviving manuscript ("K1") of an Avestan language text is dated 1323 CE. Summaries of the various Avesta texts found in the 9th/10th century texts of Zoroastrian tradition suggest that a significant portion of the literature in the Avestan language has been lost. Only about one-quarter of the Avestan
Avesta year, the third is recited at the six seasonal feasts, and the fourth at the beginning and end of summer. All material in the "Avesta" that is not already present in one of the other categories falls into a "fragments" category, which – as the name suggests – includes incomplete texts. There are altogether more than 20 fragment collections, many of which have no name (and are then named after their owner/collator) or only a Middle Persian name. The more important of the fragment collections are the "Nirangistan" fragments (18 of which constitute the "Ehrbadistan"); the "Pursishniha" "questions," also known