The Mother See of Holy Etchmiadzin is the pre-eminent center of authority in the worldwide Armenian Apostolic Church. Located near the capital of Yerevan in the Republic of Armenia, it is composed of:
The Mother Cathedral of the entire Armenian Church;
The monastery and monastic brotherhood;
The residence of the Catholicos of All Armenians;
Various religious and cultural institutions, such as the Kevorkian Theological Seminary and a museum
The cathedral dates back to the 4th century, and is reckoned the oldest Christian cathedral in world. Although the current sanctuary was erected in the 1600s, remnants of the 4th-century altar have been unearthed beneath the present structure.
In its capacity as the residence of the Supreme Patriarch and Catholicos of All Armenians (the pontiff of the Armenian Church), Holy Etchmiadzin is known as the "Catholicate of All Armenians." It became the seat of the Catholicate of the entire Armenian nation in the 4th century, following the conversion of King Tiridates III to Christianity by St. Gregory the Illuminator in AD 301.
According to the chronicler Agathangelos, soon after Armenia's conversion to Christianity, St. Gregory had a vision of the Son of God. Appearing as a heroic figure of light surrounded by a mighty angelic host, Christ struck the ground with a golden hammer, indicating the place where the Mother Cathedral of the new Christian nation was to be established. The name Etchmiadzin--literally, "where the Only Begotten descended"--refers to this episode.