TL was a time scale used by the Time Lords. It was used in The Dalek Problem, a historical analysis of the Daleks by Qualen. (PROSE: The Dalek Problem)
History
In 66,300 TL, two tribal cultures of the planet Skaro, the Kaleds and the Thals, first encountered one another and engage in war, devoting almost all of their scientific effort for the next 1,000 years toward the development of advanced weapons.
Circa 67,300 TL, the Kaled/Thal civil war, having escalated into the use of primitive, but effective, uranium fission devices, destroys most of the planet's habitations. Skarosian civilization is nearly destroyed, with the remnants of the two cultures reduced to a pre-atomic level of warfare through lack of nuclear hardware or the sophisticated means to manufacture it. The war continued with more conventional weapons, though the planet itself was so poisoned with radiation that uncontrolled and mostly lethal mutations were widespread among the first post-nuclear generation
In 67,328 TL, in the original timeline of Skaro, the Thals used a rocket bomb to attack the last Kaled city, but a protective coating developed by Kaled scientists permitted the city dome to resist the bom- bardment. In the flush of victory, the Kaled leaders permit Davros, a leading scientist, to unleash his latest creation against the helpless Thal city. Davros, a genius cyberneticist and geneticist, has studied the radiation-spawned mutations in the Kaled race and predicted the ultimate form of the race's development. Bypassing thousands of years of natural selection, Davros creates the Daleks, with a force of prototypes being sent to destroy the remaining Thals. With the Thal city taken and the Thals exterminated, Davros named himself ruler of Skaro but his rule was short-lived; as the Daleks had been programmed to hate all life, they soon turned on their creator and the rest of the Kaleds, exterminating them in turn. According to projections made by the APC Net, the Daleks then went on to eventually threaten Gallifrey itself and possibly conquer the universe.
The infamous Deliavatsud Intervention changed this course of events. Deliavatsud stole an experimental Time Ring from the Temporal Development Center and gave it to the Fourth Doctor for use as a location device for Rassilon's Time Scoop. Deliavatsud then illegally used the Scoop to send the Doctor and his companions to Skaro just before the Daleks were first activated. After the Doctor hesitates to destroy the nascent Daleks, the Thal city is still ravaged by the Daleks, but difficulties caused by the Doctor's intervention caused Davros himself to turn on his fellow Kaleds and assure the destruction of their city as well. Thals who survived the destruction of their city attack and managed to seal the Daleks inside an underground bunker with their Davros, the Daleks' attempt to kill him placing him in suspended animation.
Circa 67,900 TL, the Daleks who were buried under-ground in the last desperate battle with the Thals returned to the surface to recapture Skaro from the Thals, though Davros remained lost in a deeper vault in suspended animation. The remnants of Thal technological civilization were destroyed, and the survivors returned to a barbaric existence in the deep wilderness areas of the planet. In the next 1,500 years, the Daleks were able to recover their own Kaled-spawned technology to the levels that existed before the Kaled/Thal atomic war, using atomic technology to launch orbital spacecraft and explorations of the worlds of the Skaro system.
In 68,500 TL, the development of hyperdrive leads to a major disagreement between two factions among the Daleks. The Expansionists decided to use the new hyperspace ships to expand their dominion to the stars. The Exterminators elected to remain on Skaro to continue hunting down their the Thals. The Exterminators became clumsy and careless, finding no real challenge in combating the scattered and disorganized Thal encampments. The Expansionists, however, were hardened by their life of conquest and became even more cunning and ruthless.
In 68,633 TL, a Dalek expedition discovered valuable metal deposits on Temporal Nexus Point Tliir and conquered the planet, enslaving the native Twiil race. This dangerous situation was discovered by CIA operatives assigned to watch this Temporal Nexus Point and reported to the CIA in basetime 101,193 TL.
In 68,639 TL, a Twiil colony world in the same solar system as Tliir counterattacked against the Daleks. Not expecting armed resistance from space, the Daleks were defeated. Time Lady Loribetcazistanopilain, having convinced the Council not to directly intervene against the Daleks, acts as adviser to the colonial forces. As a result, the Tliir were liberated in 68,641 TL after only six years of Dalek rule and a disastrous two-year war.
In 70,073 TL, the Exterminator Daleks of the major Skarosian city, having become weak and decadent after years with no serious opposition, were defeated and destroyed by a small but well-prepared group of Thals. This marked the beginning of the end for the Skarosian Daleks. The Thals began adapting captured Dalek technology for their own uses, and, by 73,000 TL, they had an interstellar fleet of their own, quickly catching up with the Daleks in war capability.
In 70,092 TL, first contact was made between the Daleks and the Ogrons, who would become the Daleks' allies in many conquests and plots.
By 72,872 TL, the failure of the Deliavatsud Intervention had led to the Daleks being allowed to spread throughout Mutter's Spiral, leading them eventually to Temporal Nexus Point Earth. A major Dalek attack force easily overwhelmed the divided and quarrelsome nations of Earth at a time before the human inhabitants had developed technology capable of dealing with the Dalek threat. Ironically, the Dalek defeat was eventually brought about because the Daleks relied too heavily on Robomen for policing their conquered world. A human underground succeeded in disabling the central contro! for the Robomen and recapturing their world. Certain elements within the CIA seized on this incident as an excuse for promoting more ill-considered interventions, but cooler heads prevailed for the most part, and the CIA remained on a steady course of researching interventions thoroughly before proceeding with decisive action.
In 73,208 TL, a major invasion of Mutter's Spiral was prevented by a Thal Revenge Squad that intercepted and destroyed the bulk of the Dalek army on the planet Spiridon.
In 73,314 TL, the last of the Exterminator Daleks was destroyed by Thal forces. The war left Skaro barren, however, and the Thals themselves abandoned it for more hospitable worlds.
In 73,508 TL, a Dalek attempt to spread a plague throughout Mutter's Spiral was blocked by the actions of certain Earth humans. The failure of this effort strengthened the position of CIA observers who called for a long period of study before initiating action against the Daleks.
Circa 74,480 TL, the Expansionist Daleks developed time corridor technology, thus giving them the ability to make limited intervention attempts in time. Though the time corridor was recognized as a potential threat, the CIA determined that the Dalek time travel device was nowhere near as efficient and versatile as even the crudest TARDIS devices. (PROSE: The Dalek Problem)
In 74,513 TL, the Daleks launched their first inter-temporal intervention, against Temporal Nexus Point Bav in the year 42,005 TL. The loss of a minor-level CIA operative prompted overly hasty action by the CIA, with Lady Loribetcazistanopilain intervening in a non-violent exchange of data between the Daleks and the natives of Bav, the Ka. Projections of the results of the contact from basetime Gallifrey revealed the eventual defeat of the Daleks by the Ka, but the Loribet Intervention prevented this, assuring the quiet extinction of the promising race, though not at the hands of the Daleks.
In 74,066 TL, infamous 666 Plot was launched by Dalek temporal intervention in the timeline at Temporal Nexus Point Teth in 67,666 TL, with Dalek scientists attempting to discover the secret of telepathic domination as practiced by the dominant Bruul upon the marginally-intelligent Klevits.
In 74,708 TL, the Daleks, finding themselves without the resources to dominate Mutter's Spiral alone, launch a Master Plan to unite other races of the universe against Earth, with an assault against Gallifrey itself believed to be in their long-range plans. The Dalek plan failed when their Time Destructor device destroyed itself upon firing.
Circa 75,100 TL, first contact occurs between the Daleks and the Movellan Empire, which immediate leads to the outbreak of the Dalek-Movellan War, thus distracting both from expanding elsewhere and disrupting other timelines.
In 75,208 TL, a Dalek expedition returned to the site of the bunker where they began on the Skaro, in search of the buried crypt where Davros resided in suspended animation. A Movellan strike force arrived to stop their Dalek foes from obtaining aid from their creator. During the confrontation, human slaves being used for excavation staged a revolt against the Daleks. Once again, Movelian and Dalek forces got in each other's way and were both defeated. Davros was captured by the humans and returned to the human Federation for trial. The Dalek creator stood trial, after which he was imprisoned in suspended animation aboard a special space station.
In 75,255 TL, the primary war fleet of the Daleks is contaminated and destroyed by a deadly virus developed by the Movellans. Scattered groups of uncontaminated Daieks fled to hidden outlying colonies and scrambled to avoid contamination, removing them, at least temporarily, as a galactic threat. The Movellans, now with hundreds of former Dalek worlds to loot, also ceased to be a threat to the timeline. The situation continued to be observed by vigilant CIA observers.
In 75,299 TL, a desperate Dalek attempt to free Davros so he can find a cure for the Movellan virus failed and resulted in the apparent destruction of both Davros and the small Dalek assault force. The incident, however, pointed to the inescapable conclusion that the Dalek threat remained constant. The Time Lord Council begin gathering data on the Daleks that was cleverly siphoned off and reorganised by CIA operatives under the direction of the Office of Multihistorical Research.
In 101,197 TL, CIA Director Deliavatsud queried the APC Net about Dalek expansion, which leads him to attempting his intervention. The intervention fails, and the Daleks, after a short delay, are set loose upon the universe anyway. The Time Lord High Council of Gallifrey investigated the blatant intervention by Deliavatsud. The Doctor's participation was reviewed and he was held blameless on technical grounds, as Deliavatsud supposedly forced the Doctor to participate. Deliavatsud himself, however, was executed by disintegration for the crime of unauthorized intervention. The result of Deliavatsud's "foolish" mistake was to force all CIA temporal intervention activities underground, handicapping the organisation for many years to come. A review of Deliavatsud's notes on his decision revealed previous unauthorised meddling by the Doctor. Much of Deliavatsud's work was lost when it was seized and destroyed by the High Council, necessitating a new survey of the Dalek Situation be made. The task is given to Lord Qualenawtivanastech, respected scholar and newly-appointed Chief of Multihistorical Research for the CIA.
In 101,209 TL, the findings of the survey of The Dalek Problem were published after over a decade of careful study by the Qualen Commission. (PROSE: The Dalek Problem)
Behind the scenes
Gallifrey's TL relates to Earth's BC/AD dating system using the following mathematic formulas
- When TL is greater than or equal to 70,709: A.D. = TL — 70,708, TL = A.D. + 70,708
- When TL is less than 70,709: B.C. = 70,709 — TL, TL = 70,709 — B.C.
The Cybermen.