Etchmiadzin Monastery, also known as the Mother Cathedral of Holy Etchmiadzin, is the spiritual center of the Armenian Apostolic Church located in the city of Vagharshapat, Armenia. It was founded in the early 4th century by St. Gregory the Illuminator, who converted King Tiridates III and the people of Armenia to Christianity.

The monastery complex includes several churches, chapels, museums, and administrative buildings. The main church, known as the Mother Cathedral, was built in the 4th century and has been renovated and expanded several times over the centuries. It is considered one of the oldest continuously operating Christian churches in the world. The complex also includes the churches of St. Hripsime and St. Gayane, both of which were built in the 7th century and are UNESCO World Heritage Sites.

Etchmiadzin Monastery has been a major center of Armenian religious and cultural life for centuries. It is the residence of the Catholicos of All Armenians, the head of the Armenian Apostolic Church. The complex also houses a seminary, a museum of Armenian art and artifacts, and a library with a vast collection of ancient manuscripts and books.

Etchmiadzin Monastery is an important pilgrimage site for Armenians and a popular tourist destination. Visitors can attend church services, see ancient relics and artifacts, and learn about Armenian history and culture. The monastery is also a symbol of Armenian national identity and a UNESCO World Heritage Site.