Dunno if this has been discussed before (I found none on search, so), but all these are rooted by a simple question of mine: How old is Martin during the Oblivion Crisis?
Uriel definitely can't have a child during the Imperial Simulacrum (389-399) so that makes Martin younger than 34 or older than 44.
We know that in his 'youth' he entered the Mages Guild, grew impatient of its restriction, and end up worshiping Sanguine. But how old was he at those times, really? How old is considered 'youth' and 'advlt' for men in Cyrodiil? Age limitation of the MG? Uriel himself ascended to the throne at the age of 22, so does that mean it's fairly possible for Martin to be at most 34? Entered MG late teen, worshiped Sanguine early-mid twenties, became a priest mid-late twenties or even older (for all those accounts)?
From what I've seen around forums and fics though, Martin is depicted to be much older than that, and imho, his physical appearance support that
So, at least 44? But Jauffre said "From time to time he (Uriel) would ask about the child (Martin)'s progress," so he'd actually be considerably much older than 44. Let's just assume around 54, cause Jauffre would certainly notice if Uriel stop asking about his son out of the blue, right? So he's about as old as his half-brothers, and considering that they as the legit Imperial heirs barely doing anything (except crown prince Geldall) including child-making, well, it makes sense. Poor Empress Caula though, being cheated on while she was busy doing labors... (unless she died after giving birth to Ebel, as stated in PGE3)
...
And now, for the conspiracy theories.
What if Jagar Tharn as the Imperial Battlemage, know about Martin's existence? And he, imposing as Uriel, keep asking Jauffre about Martin? But why would Jauffre said that Uriel asked about Martin, given that he's aware that he's reporting to an impostor? (Memory problems at old age? )
But oh no, my imagination runs wilder. What if Jauffre's the one who told Jagar about Martin? Unaware about the fake and all... And well, by extension, this incident make Dagon and Mythic Dawn also aware of the illegitimate heir. Seriously though, even Jauffre said "If the enemy is aware of his (Martin) existence, AS SEEMS LIKELY"
MD seems to know about all of the Blades' secret, but what if this one intel was given involuntarily? Was Jauffre a MD uncooperative asset? Much like Ulfric to Thalmor? Is this a recurring character trope in TES???
Thoughts?