The Intuitive Revelation was a period of Gallifreyan history.
Before the Revelation, Gallifrey was a matriarchal society ruled by the Pythia through magic and superstition. The Triumvirate decided it was better to promote reason and science. This led to the Intuitive Revelation, where they overthrew the Pythia, with Rassilon gaining the most influence in the aftermath. (PROSE: Cat's Cradle: Time's Crucible)
Following the Revelation, telepathy was used rather than speech and few individuals kept their own personality or secrets. (PROSE: Cat's Cradle: Time's Crucible) The monk I.M. Foreman was driven from his monastery at this time, and left Gallifrey with his Travelling Show. (PROSE: Interference - Book One, Interference - Book Two)
When the Seventh Doctor returned to the House of Lungbarrow, Innocet told Chris Cwej that the Houses were believed to be the oldest living things on Gallifrey, the first ones having been grown during the Intuitive Revelation. (PROSE: Lungbarrow)