Dayro d-Mor Mattai (Syriac: ܕܝܪܐ ܕܡܪܝ ܡܬܝ;The Monastery of St. Matthew, Arabic,دير مار متى) is located atop Mount Alfaf in northern Iraq and is 20 kilometers from Mosul. It is recognized as one of the oldest Christian monasteries in existence.
Mor Timothy Mosa Alshamany (2015), Arc bishop of the monastry
The monastery was founded in 363 by the hermit, Mar Mattai who had fled persecution in Amid under the Roman Emperor Julian the Apostate. According to Syriac tradition, he was involved in healing the sister of Mor Behnam and converting the brother and sister to Christianity. Their father, king Sennacherib of Assyria initially killed his son and daughter but later recanted and awarded Mattai a place atop Mount Alfaf to establish his monastery. Mattai was quickly joined by a small Syriac followers, and under his leadership that community developed a true monastic ethos.
The monastery is famous for its magnificent library and considerable collection of Syriac Christian manuscripts. In 1171, the Kurds attacked the monastery and several manuscripts were damaged, some who survived were taken by monks to Mosul. In 1369, another Kurdish attack on the monastery damaged further manuscripts. During the 19th century, Kurds looted the monastery several times.
The monastery is currently maintained by the Syriac Orthodox Church. Every year, Christians of various church denominations gather in the monastery on September 18 to commemorate the day of Mar Matti's death.