two principal cities of the Mokrian dialect area. Zazaki and Gorani Zaza–Gorani languages, which are spoken by communities in the wider area who identify as ethnic Kurds, are not linguistically classified as Kurdish. Zaza-Gorani is classified as adjunct to Kurdish, although authorities differ in the details. groups Kurdish with Zaza Gorani within a "Northwestern I" group, while Glottolog based on Encyclopædia Iranica prefers an areal grouping of "Central dialects" (or "Kermanic") within Northwest Iranic, with Kurdish but not Zaza-Gorani grouped with "Kermanic". Gorani is distinct from Northern and Central Kurdish, yet shares vocabulary with both of them and there are some grammatical similarities with Central Kurdish. The Hawrami dialects of Gorani includes a variety that was an important literary language since the 14th century, but it was replaced by Central Kurdish in the 20th century. European scholars have maintained that Gorani is separate from Kurdish and that Kurdish is synonymous with the Northern Kurdish group, whereas ethnic Kurds maintain that Kurdish encompasses any of the unique languages or dialects spoken by Kurds that are not spoken by neighbouring ethnic groups. Gorani is classified as part of the Zaza–Gorani branch of Indo-Iranian languages. The Zaza language, spoken mainly in Turkey, differs both grammatically and in vocabulary and is generally not understandable by Gorani speakers but it is considered related to Gorani. Almost all Zaza-speaking communities, as well as speakers of the closely related Shabaki dialect spoken in parts of Iraqi Kurdistan, identify themselves as ethnic Kurds. Geoffrey Haig and Ergin Öpengin in their recent study suggest grouping the Kurdish languages into Northern Kurdish, Central Kurdish, Southern Kurdish, Zaza, and Gorani, and avoid the subgrouping Zaza–Gorani. The notable professor Zare Yusupova has carried out a lot of work and research into the Gorani dialect (as well as many other minority/ancient Kurdish dialects). History During his stay in Damascus, historian Ibn Wahshiyya came across two books on agriculture written in Kurdish, one on the culture of the vine and the palm tree, and the other on water and the means of finding it out in unknown ground. He translated both from Kurdish into Arabic in the early 9th century AD. Among the earliest Kurdish religious texts is the Yazidi Black Book, the sacred book of Yazidi faith. It is considered to have been authored sometime in the 13th century AD by Hassan bin Adi (b. 1195 AD), the great-grandnephew of Sheikh Adi ibn