Step of Silence
From Halopedia, the Halo wiki
The Step of Silence is a massive chamber inside the Sanctum of the Hierarchs of High Charity specially designated for the High Prophets. The Step of Silence is a large, round room with an illuminated pedestal in the center. Suspended from the ceiling are hundreds of shards of glass, each a piece of a planet that has been glassed by the Covenant. On the perimiter of the room, there is space for three hundred Honor Guard Elites, should a Prophet be present.
The first time the High Prophet of Truth and Tartarus are ever mentioned in the Halo universe is when they are in the Step of Silence, which is the last chapter of Halo: First Strike. They discuss the events of Installation 04, as well as the fate of the future Arbiter and Operation: FIRST STRIKE.
