Etchmiadzin Cathedral is the mother church of the Armenian Apostolic Church, located in the city of Vagharshapat (Etchmiadzin), Armenia. According to most scholars, it was the first cathedral built in ancient Armenia and is often considered the oldest cathedral in the world. According to tradition, the original church was built in the early fourth century—between 301 and 303—by Armenia's patron saint Gregory the Illuminator, following the adoption of Christianity as a state religion by King Tiridates III. It was built over a pagan temple, symbolizing the conversion from paganism to Christianity.