This area, the 10/40 window, was historically Christian until the Muslim despot Tamerlane and his sons started a genocide in the 12th century that killed off most of the Church of the East, including all of its populations in Yemen, south Arabia, Central Asia, Mongolia, China and Tibet, leaving only the Mar Thoma Christians in Kerala, India, and the Assyrian Christians in the Fertile Crescent, who in both cases are members of the present day Syriac Orthodox Church and the Assyrian Church of the East (and the smaller Ancient Church of the East) and various Eastern Roman Catholic churches.
There are many Christians in the 10/40 belt, although they are experiencing substantial persecution, at the moment this has become particularly severe in Syria since the fall of the brutal Assad dictatorship and its replacement with an even more brutal Islamist regime, and also in Armenia, where Azerbaijan just invaded and ethnically cleansed the historic Armenian territory of Ngorno-Karabakh.
