Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Church of the Holy Cross was a cathedral of the Armenian Apostolic Church, built as a palace church for the kings of Vaspurakan and later serving as the seat of the Armenian Catholicosate of Aght'amar. During his reign, King Gagik I Artsruni (r. 908-943/944) of the Armenian kingdom of Vaspurakan chose the island of Aght'amar as one of his residences founding a settlement there. The only structure standing from that period is the Cathedral. It was built of pink volcanic tufa[citation needed] by the architect-monk Manuel during the years 915-921, with an interior measuring 14.80m by 11.5m and the dome reaching 20.40m above ground.