Dayro d-Mor Mattai (Syriac: ܕܝܪܐ ܕܡܪܝ ܡܬܝ; Arabic: دير مار متى; The Monastery of St. Matthew or Dayro d-Mor Mattai)[1] is a Syriac Orthodox Church monastery on Mount Alfaf in northern Iraq.

The monastery was famous for the number of monks and scholars it housed, and for its large library and considerable collection of Syriac Christian manuscripts.

The monastery was founded in 363 AD by Mor Mattai the Hermit who fled persecution in Amid under the Roman Emperor Julian the Apostate with 25 other monks and took residence in Mount Alfaf.

He killed his son and daughter when he learned they became Christians, but he later recanted and built a church and a monastery per Mor Mattai's request on the Mount Alfaf.

In the 12th century, after storming a nunnery in Khudida, Kurds attacked the monastery for four months with 1,000 horsemen and foot soldiers.

Every year, Christians of various church denominations gather in the monastery on September 18 to commemorate the day of Mor Mattai's death.

The first synod was held to renew the union between the Mor Mattai Monastery and the Syriac Orthodox Church.

The Synod discussed post-war challenges such as the huge numbers of refugees, issued new canon laws, and sought to organize church affairs.

Particular challenges included managing properties and endowments in different emerging nation-states in the Middle East and the globally scattered diaspora.

This office was abolished in 1860, by which time it had become a titular see, due to the decline in population of Syriac Orthodox Christians in the region.

[3] This is a list of Syriac Orthodox church metropolitans and bishops that studied and graduated from Mor Mattai Monastery but served in different dioceses.

[3] This is a list of Syriac Orthodox Church fathers and other clergy that are buried in Mor Mattai Monastery:[3]