Virgin reality

A sequence in the Seventh Doctor's life, broadly spanning his fight with the Timewyrm to his visit to the House of Lungbarrow, crystallized a version of reality into existence, (PROSE: Deceit, Blood Heat, Falls the Shadow, So Vile a Sin, et al.) known by some as the Universe (PROSE:  Genesys,  Apocalypse, Deceit) or the real universe because it was the only normal universe in existence. (PROSE: Blood Heat, No Future, Falls the Shadow, Dead Romance) Due to the process of crystallized time, other attributes of this reality included a version of human history leading into the Earth Empire, (PROSE: Blood Heat, The Dimension Riders) a version of Time Lord history involving looms, (PROSE: Cat's Cradle: Time's Crucible, et al.) the subsequent sequence of Bernice Summerfield's life on Dellah, (PROSE: Oh No It Isn't!, Ghost Devices, Dead Romance, et al.) and various other adventures of the Seventh Doctor's prior incarnations. (PROSE: The Crystal Bucephalus, The Well-Mannered War, A History of the Universe, et al.)

While the majority of sources indicated this reality was the same universe as the Doctor's universe as a whole, (PROSE: Vampire Science, Demontage, System Shock, Notre Dame du Temps, AUDIO: Enemy of the Daleks, The Prisoner's Dilemma, WC: Shadow of a Doubt, et al.) some indicated it was separate from other major strands of the Doctor's existence. (PROSE: The Eight Doctors, Interference - Book One, Dead Romance, Celestial Intervention - A Gallifreyan Noir, At Childhood's End, AUDIO: Auld Mortality, Signs and Wonders, et al.)

By some accounts, this sequence of the Doctor's life continued into a sequence of the Eighth Doctor's life beginning with his travels with Sam Jones, (PROSE: Vampire Science, The Scarlet Empress) which initiated a new version of reality. (PROSE: The Eight Doctors, Unnatural History) Similarly, the sequence of Bernice Summerfield's Dellah life segued into her time with the Braxiatel Collection in an altered reality. (AUDIO: Professor Bernice Summerfield and the Mirror Effect, The End of the World, et al.)

Origins
By many accounts, this reality was created out of crystallized time, with each landing of the Doctor's TARDIS crystallizing the visited events into certainty. (PROSE: Deceit, Blood Heat, Falls the Shadow, So Vile a Sin, et al.) Notably, an early event in this sequence of the Seventh Doctor's life brought him into contact with ancient Gallifreyan history, with the Doctor's communication with the 508th Pythia motivating her to unleash Pythia's Curse and initiate the version of history where Time Lords came from looms; (PROSE: Cat's Cradle: Time's Crucible) the Curse then rippled through the space-time fabric of the Doctor's present, indicating this too was a crystallized event which was had not always been the single history. (PROSE: Transit)

One account showed that this reality was a bottle universe created by I.M. Foreman. (PROSE: Interference, Dead Romance) The phenomenon of time needing to be crystallized, by this account, was a sign of the bottle not containing enough biodata for a complete history. (PROSE: The Cosmology of the Spiral Politic)

Behind the scenes

 * Early Big Finish Productions stories featuring Bernice Summerfield were branded as Side Steps into "Virgin territory".
 * Steven Moffat has described the Virgin New Adventures as "a separate (and equally valid) continuity" to the modern BBC Wales TV series.