This grand temple contains the sacred shrine of Sheikh Adi, the prophet of Ezidism. It synthesizes regional elements in an Ezidi way: the springs and flames inside recall Zoroastrianism; the main hall recalls a church nave; the walls have Ottoman and funerary carvings.
It has been destroyed, rebuilt, and renovated numerous times over the centuries — even into the 20th century. Indeed, photos show that its stone blocks have been rearranged again and again. It is unclear what existed on the temple grounds previously, but since Sheikh Adi was born not-so-long-ago, it is possible the location was used or shared previously by other religions as well.
The term Sheikh among them corresponds to Mar among the Christians of the Syrian church, whether Nestorian, Jacobite, or Maronite, and Saint in English. For instance, the convent of Mar Mattai, so called by the Christians, is uniformly Sheikh Mattai among the Yezidees, and translated into English would be St. Matthew. So the temple of Sheikh Yohanna at Sheikh Adi would be Mar Johanna among the Christians. Some of the latter believe that in ancient times there was a church here dedicated to St. John; others say that one of the apostles founded it and gave it that name, and they selected Thaddeus -- in Arabic تادای, whence they say came Adai or Adi -- as the founder. The Yezidee Kehyah of Basheeka said that the door leading out from under the dome at Sheikh Adi, (it was so dark we did not enter,) led into a room where was a stone with inscriptions showing that it was once a Christian monastery dedicated to Sheikh Hannah or Anna (St. John). Laurie 1848, p 148
The sequence of areas and rooms upon entering the temple are as follows,
Laurie, Thomas. 1848. Bibliotheca Sacra and Theological Review, Volume 5. https://www.google.com/books/edition/Bibliotheca_Sacra_and_Theological_Review/PzdSAAAAYAAJ
Article on Daya Shirin, a 92 year old woman (-) who had served in the shrine for 62 years.