Church of Saint Jacob of Nisibis

Mar Yakov Church or Mor Yakup Church (Syriac: ܥܕܬܐ ܕܡܪܝ ܝܥܩܘܒ ܕܨܝܒܝܢ Idto d-Mor Ya'qub d-Nsibin, Turkish: Mor Yakup Kilisesi), also known as the Church of Saint Jacob in Nisibis, is a historic church in Nusaybin, southeastern Turkey. Archaeological excavations revealed that the 4th-century church building was originally the baptistery of a cathedral, which no longer exists.

Source: Wikipedia — Church of Saint Jacob of Nisibis (CC BY-SA 4.0)