Phase IV: Nabataean Grand Design: 1st c. BCE to CE 1st c. The remainder of the subterranean canalization is installed including the East Plaza Great Cistern. The East and South Perimeter Walls are installed and Rooms A and B and the Tabun Cave Room are built into the casemate of the East Perimeter Wall. The East Plaza and South Passageway are paved and the temple Forecourt is raised and laid with a small hexagonal pavement. Residential Quarter is built in the southwest corner of the precinct. Also at this time the Central Staircase of Phase II is blocked and the lateral East and West Staircases are constructed to access the Lower Temenos.