Theory talk:Timeline - The Monk
LOL. He was never stranded on an ice planet. At the end of The Daleks' Master Plan he states that he's destined to wander the universe, as the Doctor took his directional control.
So, whoever "Mortimus" from No Future is, it's not the same guy from The Time Meddler.
Also, in No Future, the "Mortimus" there states that he never knew the Doctor kn Gallifrey. While in Divided Loyalties, the "Mortimus" there is good friends with the Doctor on Gallifrey.
Now, go and read the end of Divided Loyalties. The 'Mortimus' section. Do you see it? The Mortimus in Divided Loyalties was trying to help the Norman's in 1066, whereas the character in The Time Meddler was trying to prevent the Norman Invasion. So, these two people were working against each other.
In Thd Book of Kells the Eighth Doctor says he hasn't seen the "Monk" for several regenerations, and that the two never met on Gallifrey.
But in The Rani Elite, the Sixth Doctor reminisces about his old friend Mortimus, from Gallifrey.
In 4-Dimensuonal Vistas, the Fifth Doctor refers to the other Time Lord as "the Time Meddler, and it's somebody he knows, but not well.
In one of Hound's audios it is stated that the Doctor is the only person who calls Hound "the Monk", yet Garden introduces himself to everyone as "the Monk".
So, it's not a "non-linear" timeline. It's not "wibbly wobbly timey wimey". It's an impossible mess, with numerous irreconcilable contradictions, that no Time War or Cracks in Time can fix.
Leaving aside the "story x isn't canonical" idea, the only solution is that there are multiple characters, different and separate from each other, called either "Mortimus", "the Monk", "the Time Meddler" etc. At least 2 of them were in 1066, at least 2 of them are called "Mortimus". And the Doctor, and others,may confuse them. But it's NOT all the same person.