Ages of Discovery
Ages of Discovery are time periods in Covenant history where great technological advancements or discoveries of Forerunner relics are made. It is believed that during one of these Ages, the San'Shyuum (possibly with the help of the Huragok), discovered the existence of the Halo Array, giving birth to the Covenant religion, with its central theme that its activation would begin the Great Journey for the Covenant, leading them to salvation. What they did not know is that activating the array would lead to the destruction of all sentient life in the galaxy.
The Twentieth Age of Discovery occurred in the late 21st century. It was during this period, circa 2070, that the Ardent Prayer was constructed.  The Shadow of Intent was built during the Third Age of Discovery, circa 2135.
Progression of the Ages
Leader, or Chieftain: Discovery.
Congregation, or Pack: Fourth! Wonder and understanding!