The Monastic Complex of Khor Virap ("deep pit") is situated on a hill of Khor Virap near the early Armenian capital city of ancient Artashat built by king Artashes I around 180 BC. Katholikos Nerses the Builder constructed the smaller S. Gevorg church in 642. In this church are two deep stone cisterns, which are said to have been the pit in which Gregory the Illuminator was imprisoned by the cruel King Trdat. Grigor cured the King and was released; he converted him to Christianity, and in 301 Armenia adopted Christianity as the state religion. So, Armenia was the first state in the World to adopt Christianity. The central church S. Astvatsatsin dates from the end of the XVII c. Khor Virap was an important educational center in medieval times. It remains a pilgrimage site up to the present day.