It is located 30km miles northeast of Mosul on Maqlub Mountain in northern Iraq.

It is cared for by the Chaldean Church (previously The Church of the East)

Deir Mar Mattai is considered to be the most important Assyrian monastery in Iraq due to its religious, historical, and geographical significance. Located at the top of Maqloub Mountain, the monastery overlooks the magnificent fields of the Nineveh plains. To the left of the monastery is a large cave with a natural spring.

The monastery has over 50 rooms, 3 halls for gathering, a church, a saints' room (Baith Qadisheh) believed to hold the remains of Mar Mattai, Mar Zakkai, Mar Abraham, Bar Ibraya among others.

It is considered the only monastery remaining with its original building. The only accurate date for the monastery actually belongs to the building of the church within it, and dates back to the mid 4th century.

Mar Mattai is believed to have been born in Diyarbakir (present day southeastern Turkey). He and other monks fled to Maqloub in 361 AD, during the reign and persecutions of Emperor Julian the Apostate. The number of monks soon increased to over 7000 which brought about the new name of the mountain, Tura D'alpayeh, or the Thousands Mountain.

In 484 AD, the monks of Mar Mattai followed the Monophisite theology (the belief that Christ had only one nature, a divine nature).

In the beginning of the 6th century, the theological direction of the monastery returned to follow the two natures theory which continues to the present. The monastery became a well known learning center from the 7th century to the 12th century.
The monks fled from the battles of Salah ed Din in the 12th century. The monastery returned to its past splendor in the 13th century until its partial destruction by Tamerlane in the late 14th century.

The monastery remained abandoned until 1795 AD when it was renovated, and in 1845 it was expanded. The monastery is still considered to by one of the most sacred places of Christian worship in the Middle East. Christians belonging to the Assyrian church of the East, the Chaldean Church, the Syriac Orthodox Church, and well as other Assyrian churches frequently visit Deir Mar Mattai for spiritual healing and meditation.


source: www.chaldeansonline.net/iraq/syriac.htm