Hypothetically if Robert had gotten to King's Landing before Tywin's forces then what would he have done to the targaryen children? Also what would Stannis have done if he was in such a position?
If Robert had reached King’s Landing before Tywin, then baby Aegon would sent to the Wall, Rhaenys would be forced into the Faith in some secure bastion of loyalist rule (either White Harbor or, more than likely, some remote village in the Stormlands with the abbess instructed to watch her communications closely). Elia would have been returned to Doran Martell with a two-year prohibition on marriage, same as Jeyne Westerling as part of Doran’s oaths to the new ruling regime. I foresee Stannis doing the same thing, though given his prospective treatment of Sansa, he might send Elia back to Doran before the oaths of vassalage as right and proper conduct.
As we see in Robert’s reign in OTL, it takes more than just the existence of Targaryens for him to actually do anything about it.
Thanks for the question, Anon.
SomethingLikeALawyer, Hand of the King