Mapper

The Mappers were a "guild" of cartographers created by the Great Houses early on in the history of the Homeworld. Auteur was said to have originally been a Mapper, although Intrepid believed this was a tall tale he had invented to give himself more gravitas.

Origins
After the Anchoring of the Thread, the Great Houses had succeeded in shaping the broad arc of History, but, in the process, had made the Spiral Politic into a fixed "vast expanse" that they needed to explore if they were to call themselves Lords of it. Thus, after the first few experiments which resulted in monsters and mutations, the first successful births from the Looms were devoted to the creation of Mappers (PROSE: ) in what was referred to as the Mapping Project, under the supervision of the Lord Founder, Urizen. (PROSE: )

Golden age and downfall
The Mappers were "great explorers and mapmakers, pioneers among their kind". (PROSE: ) Armed with the Observer Effect, they mapped out the meridians of Time, they built instruments such as astrolabes and "dared into the frightening mists of History", "sailing" through History's beginning and its end, (PROSE: ) exploring "the outer reaches of reality — and beyond". (PROSE: ) Once they had returned to their offices, the Mappers "doped up on any hallucinogen" and plugged themselves into the Homeworld’s computers, creating the first maps of the Spiral Politic from their memories. (PROSE: )

However, "all had been lost, some to madness, some to the horrors and wonders that roamed in those days". (PROSE: ) In fact, once their work was done, the surviving Mappers were said to have all gone insane. Like ordinary Renegades, they took on new names, but instead of meaningful titles, they took what Intrepid to be "really stupid names, all trying to work with a timekeeping theme", such as Astrolabe or Pendulum. In the end, the Mappers, "like most of Homeworld history", were forgotten about and drifted into legend. (PROSE: )

Alleged survivors
The Sixth Doctor encountered and fought an ancient, insane Time Lord called Astrolabus who claimed he had been "the first" to chart out the "meridians of Time". By then, Astrolabus was an exile, disgraced and dubbed "the Star-Taker" for having stolen The Book of the Old Time. (COMIC: ) After other confrontations with the Doctor, Astrolabus was seemingly killed by Voyager, a Lord of Life who believed the star-charts within the Book had been stolen from him by the Time Lords long before Astrolabus had taken it for himself, and held Astrolabus responsible. Because Astrolabus had tattooed the charts directly on his body, Voyager used a sandstorm to flay him alive to take them from him, leaving him dying and skeletal. (COMIC: )

A rumour existed during the War in Heaven that Godfather Auteur of Faction Paradox, infamous for his abuse of the Observer Effect, was a surviving Mapper. The story was embraced and retold by Auteur himself, who even claimed he had been the one to map the first meridian. Cousin Intrepid, however, believed it was a fabrication that Auteur had made up with his "drinking buddies" to make himself sound important, only to start believing it himself due to his insanity and partially actualise it. (PROSE: )

After the end of the Cosmic War, Auteur, who had become trapped outside the universe, once again disguised himself as "the Last of the Mappers" upon visiting the Plume Coteries' Library. Obscuring his identity as Auteur altogether, he claimed that he had been exploring the Omniverse all this time and had only now returned to the universe, unaware of anything which had happened to his kind in the meantime. He spent twenty years in the Library posing as the Mapper, having claimed that his last task before he could return home would be to map out the Library itself. Eventually, however, his apprentice Roland realised he was an impostor with motives of his own, and confronted him. After revelaing himself, Auteur explained:

This fact was not recorded in family history, however, with Roland's grandson Naimon later continuing to claim that his ancestor had been "apprenticed to the Last of the Mappers". (PROSE: )

Other realities
In Barusa's universe, the early Time Lord explorers, some of whom went mad or never returned from their journeys, were known as the Time Explorers. The Doctor's own father, Ulysses, was such an explorer. (PROSE: The Chronicles of Doctor Who?)

Behind the scenes

 * Although Going Once, Going Twice is deliberately coy about whether Auteur really is the same individual as Astrolabus, it is, at any rate, the unavoidable implication of the text that Astrolabus (a semi-legendary Time Lord who appeared in several DWM comic stories) was a Mapper.