I think that “baby swap” theory (which is what Varys claims to have happened) has merit. I think they (Varys, Elia and whoever else…) might have attempted to do it after realising the war was lost, but they were perhaps too late?

I think one of the biggest reasons for doubt is the fact that the only people whose word we have for who he is are inveterate liars, schemers, and usually do nothing that does not first benefit themselves in some way. The idea that they are doing all this to restore the “rightful monarchy” or “for the good of the kingdom” is a bit hard to swallow.

To accept Aegon as Rhaegar’s son, we have to trust Varys. Varys, who is the most untrustworthy source of information, together with Littlefinger. Varys, who left his Pentoshi home to serve a foreign king in foreign Westeros for still unknown reasons. Varys, who can’t have a family himself, but whose oldest and closest friend, maybe as close as a brother, had a wife with Targaryen features. Said friend is deeply involved in the whole Aegon/Dany/dragons/whatever affair for unknown reasons. And he acts a bit weird during the Tyrion/Haldon/Duck conversation.

Moving onto other reasons…

Why would Elia “fight like a tigress” against Ser Gregor to save….a peasant child or Ashara’s child or someone else… switched with Aegon, not even her own son?

Also, remember that Tyrion guesses Young Griff’s age to be “around 15”, while Aegon son of Rhaegar should be closer to 18 (and you can usually tell the difference between those two ages, but not always, of course).

There’s also the matter of prophecies.

“A cloth dragon swayed on poles amidst a cheering crowd.” (ACoK, one of the visions Dany sees in the House of the Undying.) As Dany later states, this is a mummer’s dragon, a cloth dragon used by mummers in their performances. What this signifies has been unclear for a long time, but now there seems to be some glimmer of clarity, both connected with Young Griff, who is apparently revealed to be Rhaegar’s son Aegon. Seeing how the words “mummer” and “mummer’s farce” means something fake in the books, the wording suggests that in fact Aegon is an unwitting imposter, perpetrated by Varys and Illyrio for their own purposes.

“No. Hear me, Daenerys Targaryen. The glass candles are burning. Soon comes the pale mare, and after her the others. Kraken and dark flame, lion and griffin, the sun’s son and the mummer’s dragon. Trust none of them. Remember the Undying. Beware the perfumed seneschal.” (Quaithe - ACoK)

The glass candles, which appear to signal a return of magic, are mentioned both in A Clash of Kings and A Feast for Crows. The suggestion seems to be that now that they can be lit once more, certain things will follow.

The pale mare shows up already in A Dance with Dragons in the form of the plague that reaches Meereen. And the rest? Kraken and dark flame would appear to be Victarion and Moqorro (called the Black Flame by the ironmen) and the sun’s son is surely Quentyn. It also seems likely that lion is Tyrion and griffin Jon Connington, who were headed towards Daenerys before Tyrion’s actions changed their mind. This could prove a very significant deviation from the events apparently seen by Quaithe.

We also have the mummer’s dragon, which would seem to call to mind the cloth dragon in the mummer’s show that Daenerys sees in her vision in the House of the Undying in A Clash of Kings. A common interpretation of this image is that it represents a false Targaryen. Indeed, Quaithe also counsels Daenerys to “remember the Undying”. A candidate for the role of this mummer’s dragon is of course the young man that is claimed to be Aegon.

So who is he, then? If not a Targaryen? I think he could be anyone, but a Blackfyre seems the most likely at the moment.

The Golden Company, a mercenary group founded by Blackfyre survivors with the express purpose of eventually seating a Blackfyre on the Iron Throne, is supporting Aegon’s claim. Although we’re told that the Blackfyre’s “male line” has died out, the odd specificity of this statement combined with the physical description of Illyrio’s late wife seems to imply that the female line survived. (Some fans speculate that Young Griff is Illyrio’s son.) The backstory of Robert’s Rebellion suggests that Varys was feeding King Aerys’s paranoia by claiming that Prince Rhaegar was attempting to organize lords to help depose him. This probably played a role in ensuring a violent transition of power, eventually eliminating (almost) the Targaryen line. If Varys is a Targ loyalist, this seems like a pretty bad move; as a Blackfyre supporter, though, his actions make perfect sense. Also, in AFFC, there is a passage that has been speculated to be a foreshadowing to “Aegon”s appearance in ADWD. Here it is: “…He forged a new sign for the yard, a three-headed dragon of black iron that he hung from a wooden post. The beast was so big it had to be made in a dozen pieces, joined with rope and wire. When the wind blew it would clank and clatter, so the inn became known far and wide as the Clanking Dragon.”

“Is the dragon sign still there?” asked Podrick.

“No,” said Septon Meribald. “When the smith’s son was an old man, a bastard son of the fourth Aegon rose up in rebellion against his trueborn brother and took for his sigil a black dragon. These lands belonged to Lord Darry then, and his lordship was fiercely loyal to the king. The sign of the black iron dragon made him wroth, so he cut down the post, hacked the sign to pieces, and cast them into the river. One of the dragon’s heads washed up on the Quiet Isle many years later, though by that time it was red with rust.”

Targaryens use a red dragon as their sigil; a black dragon is the sigil of house Blackfyre. After their defeat, the Blackfyres were diminished in number and forced across the narrow sea (“

hacked the [black dragon] to pieces, and cast them into the river”). Could this passage foreshadow the reappearance of a Blackfyre heir (“one of the dragon’s heads”) on Westeros’s Western shore, whom - given the amount of time since Blackfyres were defeated - everyone takes for a Targaryen instead (“by that time it was red with rust”)?

When I discussed this theory previously, some people pointed out to me that Varys told a dying Kevan about Aegon, and there was no point of lying to a dead man. While this is usually true, I disagree given the context.

Because it really doesn’t matter if Varys called him “fake Aegon” or “Aegon.” The point is, they can convince people to think he is Aegon, and Varys knows it. It doesn’t matter that he might be someone else (a Blackfyre and a son of Ilyrio are the most popular theories), if the plans of Varys and Ilyrio go accordingly, Young Griff will reign as Aegon VI Targaryen. He will be remembered in history books as Aegon VI Targaryen. I mean, Joffrey was officially a Baratheon, wasn’t he?

If Cersei was killing someone in hopes of placing one of her children on the throne, I hardly think she would say “My Joffrey, whom everyone thinks Robert fathered but I’m actually in an incesturous relationship with my brother and the child is his, will become King blah blah blah…” She would simply say “My son Joffrey Baratheon will sit upon the throne.” Plain and simple.

Dying or no… why would you reveal your big secret to someone you deemed dangerous enough to get rid of? Furthermore, the Red Keep is full of ears. Varys knows it better than anyone.

Another reason why Varys probably lied to Kevan is… well, we are still discussing this, aren’t we? If Varys had said ”My foreign pal Ilyrio and I are going to put a fake Aegon on the throne lol sorry,” the mystery that GRRM probably wants us to discuss would be lost.

I hope I covered everything and didn’t bore you with all these details and speculations. This is GRRM (as I always say), so we cannot say for certain whether this Aegon is fake or not, but I’m almost sure that he is.