The Monastery of Saint Thaddeus located in Chaldiran County, West Azerbaijan province is one of the most famous and most visited Armenian churches in Iran. The monastery is known as Gharah Klisa or Gharah Church among locals. Gharah in Azari means black referring to the black stones of the structure. This church built originally in 68 CE is the tomb of Thaddeus who was martyred in Armenia in 66 CE. However, the Monastery of St. Thaddeus was destroyed and rebuilt in different historical periods.
For example, Genghis Khan, the founder of the Mongol Empire (1259-1355 CE), and his grandson Hulagu Khan destroyed a large part of this structure. Later in 1319, Khaje Nasir al-Din Tosi, the minster of Hulagu, rebuilt it. The monastery was also rebuilt by the order of Shah Abbas the first to support Armenians who sought refuge inside Iran. The decorations of the structure were later enhanced by the order of Abbas Mirza, the crown prince of Fath Ali Shah, the second king of the Qajar Dynasty (1796-1925).
In 1691, the façade of the monastery was adorned with black stones and in 1810, white stones were added to the structure by Simon Beznoni, the Maku’s bishop and Father Superior of the monastery. Importantly, along with two other Armenian monuments in West Azerbaijan province (the Monastery of Saint Stepanos and the Chapel of Dzordzorthe), the Monastery of Saint Thaddeus was inscribed on the List of UNESCO World Heritage Sites in 2008.
Every year in late Tir (the first month of summer) and the first day of Mordad (the second month of summer), coinciding with the murder of St. Thaddeus, a large group of Armenians visit the monastery and hold a ceremony in his honor.