Ansillon

Identities of the Hermit
Wider identities
Ambiguous

Ansillon was the name of a highly respected Time Lord and old friend of the Doctor.

The Fourth Doctor remembered first meeting Ansillon as a hermit on a mountain (AUDIO: Blood of the Time Lords) in his childhood. (TV: The Time Monster, et al.) For a time, Ansillon was the solitary guardian of the Caves of Perdition, (AUDIO: Blood of the Time Lords) and the Doctor climbed the mountain to consult with him many times, although by some accounts this mountain was called Mount Cadon (PROSE: Timewyrm: Revelation, The Three Paths, et al.) rather than Mount Perdition. (TV: The End of Time)

In other lives, Ansillon served many different roles: among his "many other names", as Ku'an Impe he was the Watchman of the Dark; as Uba Danth he was the High Priest of the Riven Temple of the Spliced; (AUDIO: Blood of the Time Lords) and as K'anpo Rimpoche he was the abbot of a Buddhist meditation centre in England. (TV: Planet of the Spiders)

In a later incarnation, he reclaimed the name Ansillon and became the Provost of the Recusary. Ansillon remained associated with the High Council and the Keeper of the Matrix during his time at the Recusary and gave his testaments in a series of codeces. (AUDIO: Blood of the Time Lords)

By another account, the Hermit was not Ansillon or K'anpo Rimpoche but Azmael, an ancient renegade Time Lord who later died on Jaconda. (TV: The Twin Dilemma)