Web of Time

The Web of Time was the orderly co-existence of events within Time.

It was not a necessary fundamental aspect of the universe, but rather a meta-structure created and imposed on history by the Time Lords. It could not exist until Rassilon built the Eye of Harmony and used it as what has been described as "the hitching post of chronology." (AUDIO: Neverland) This probably allowed Rassilon to choose what species developed, as he did when he inprisoned the Divergence, a possible rival to the Time Lords. (AUDIO: Zagreus) While not a fundamental universal aspect, the Web maintained a balance which reflected the holistic nature of Time. (TV: The Two Doctors)

This balance could be upset, as the Web was not invulnerable; for example, the Sixth Doctor once explained that to destroy the planet Earth in 1985 would disrupt the Web of Time. Additionally, Lytton spoke of the destruction of Mondas in 1986 as "now" being a part of the Web, implying its destruction wasn't necessarily fixed. (TV: Attack of the Cybermen)

The sinking of the Titanic was part of the web of time and preventing the disaster could cause another. Because of its sinking, all later ships would have round-the-clock radio surveillance, enough lifeboats, and the International Ice Patrol would be formed. Saving the Titanic would condemn the other ships to follow. (PROSE: The Left-Handed Hummingbird)

The Doctor would interfere with the Web in different situations. When his friend Remmnex was murdered by a dagger through the eye, the Seventh Doctor rewrote history so that he died peacefully in his sleep instead and was never possessed by Villus Krull. (AUDIO: The Dark Flame)