Rustaqa or Mar Isho (Syriac: ܡܪܝ ܝܫܘܥ Mar Isho, Kurdish: Dêra reş) was a historical Assyrian village in the Shamezdin region of Hakkari, and the traditional residence of the Matran family of Shamizdin.
There are two theories about the origin of the Mar Ishu monastery. The first is that it was named after Mar Isso, a travelling Chinese monk who stayed there on his return from Kookheh where the seat of the Patriarch was around the 5th century. The second theory is that Mar Ishu was Mar Bishu’s brother who came to the area from Kamul, in the Jazira area in the 9th century. In any case, the monastery is very old, impressive and still intact, it is now known as Qara Eglise in Turkish which is the translation of what the Kurds used to call it Daira Rash or Black Monastery.
The Monastery was an important religious school for deacons and priests that came from the surrounding areas to study the Nestorian religion. Often visited by European travellers of old to learn more about the customs of the Nestorian Church, often sent by the Patriarch to the learned Mar Khnanishu.