Qara Klise or Saint Thaddeus Monastery is one of the attractions in Iran which is registered as a UNESCO world heritage.The site is significant both historically and culturally due to its great antiquity and religiously due to its importance among Christians of Iran and Armenia. It is considered one of the holiest churches among Armenians built as a memorial to saint Thaddeus, one of the 12 apostles who traveled to Mesopotamia and Persia as a preachers of Christianity back in 45 AD. According to one tradition, the Apostles Thaddeus and Bartholomew are believed to have been the first to Introduce Christianity to Armenians.

Although there is some dispute over his identity and martyrdom, some believe that he was killed some years after entering Persia by an Armenian King. A couple of centuries later probably at the beginning of 4th century AD, when Christianity became widespread in Armenia, a church was built to remember and pay homage to saint Thaddeus.

The monastery together with Saint Stepanos church and chapel of Dzordzor was registered as a UNESCO world heritage in 2008. The church has been rebuilt several times due to damages caused during centuries such as Mongol invasions and earthquake in 1319 AD. Although some remaining parts are from 10th and 14th century, most of the present structure has been a reconstruction done in 19th century by the order of Abbas Mirza, the reputable Qajar Prince. While the earlier parts mostly in the western side were built by black and white stone (hence the name black church or Qara Klise in Turkish), the new reconstruction and renovations are made of sandstone. The complex is now located in the West Azerbaijan province of Iran, south of Maku and 20 km far from Chaldoran.

The structure with two domes of different sizes and walls of black and white stone give it a magnificent look while both inside and outside walls are elaborately adorned with beautiful carving of flowers, animals and human as well as the bas-reliefs containing verses of old and New testament written in Armenian.

Whatever is the reason for its formation, the church is a glorious and respected Armenian place in Iran both considering the historical and cultural aspects.

Every year, there is a special ceremony held in the monastery in late June or mid-July when many Armenian families from Iran and Armenia visit the place and get together for some Christian rituals such as holy communion and baptism. The festivity usually lasts three days around July 14.

It is actually more than a religious ceremony as it is a time for gathering and reunion.

This year, the Commemoration of Saint Thaddeus in Qara Klise will be held in Azerbaijan, Iran in July 2013.