The monastery of Tat'ev is the religious center of the historic Siwnik' province of Greater Armenia. The main cathedral of St. Peter and St. Paul, was erected between 895-906 by Bishop Hovhannes [John] of Siwnik'. All adjacent parts of the Tat'ev complex are fortified by walls which were added to the natural obstacles of the rocky terrain and the surrounding hilltops for defensive function from invasion by the nomads. The vaulted Church of St. Gregory the Illuminator [848] abuts to the northern wall. The church of the Virgin Mary was built in the XIIth century over the vaulted ceiling of the monastery main gate and mausoleum. The memorial and the obelisk known as the Rocking Column, dedicated to the Holy Trinity, was erected in 895. The tradition of the VIIth century architectural form consisting of a central dome -- supported by four isolated columns -- was used with the addition of paired alcoves replacing the corresponding columns supporting the dome. The monastery has often been left in ruins as a result of the invasions of the Seljuk Turks and as well as natural phenomenon such as earthquakes. The belfry toppled after the earthquake of 1931. Restorations are currently taking place in order to restore the Church of Tat'ev to its former glory.