Zeyrek Mosque ( Pantocrator Monastery) is on the left hill walking to Unkapani from Valens Aqueduct. The big complex consists of three buildings side by side was built in the 12th century. Eirene, first wife of John II Komnenos (1118-1143) and daughter of Hungarian King Ladislaus I built the first church in the south. After the death of Eirene, John II Komnenos built a smaller copy of the church to its north. The emperor decided to combine these two churches when two churches happen to be very close to each other. He built the tomb chapel between these two churches in 1136 where Emperor and Empress had been buried.  

Northern and southern churches have a plan of closed cruciform.Central spaces are covered by domes with high pulleys, and also narthexes were added to the west side. Northern church of the complex functions as a mosque today.