The Six-Fold-Realm, which human physicists knew as Calabi-Yau Space, were the six higher dimensions that were separated from the ordinary five by the Ancient Covenant. In the Six-Fold-Realm, the Council of the Guardians of Time were the Six-Fold-God. All Transcendental Beings lived and fed on the energies within the Realm, save for the Chronovores who lived in the Time Vortex but might feed in the Realm. Both the Six-Fold-Realm and N-Space were inextricably linked by the Vortex.
Ancient Covenant
The Ancient Covenant governed transcendental beings' behavior, seeming to be the physical laws set down after Event One. The Time Lords were aware of the Covenant, which forbade them from attempting to reach the Six-Fold-Realm. It also forbade the union of Eternals and Chronovores, the former exiling the latter after seeing them as parasites on the Realm. (PDA: The Quantum Archangel)