While discussing the possibilities and impossibilities of exchanging Royal offspring and heirs in times of turmoil is amusing, it doesn't bring you much further in search for the truth. What you accept as possible is your point of view and so called proofs usually are pretty flimsy. Looking at the usual suspects, though, might give you some new ideas as to whether it should or could have been done or not.
For years, astronomers have tried to puzzle out what made three astrologers travel from Persia to Israel at a certain date 2,000 years ago. Missing data, unclear sources, later additions and elisions, and religious bias make the job just more interesting. But are astronomers the right people to unravel an astrological puzzle?
Christina of Sweden was five when her father King Gustav II Adolf fell in the battle of Lützen. Upon his death, her mother Queen Maria Eleonora was put under house arrest and exiled to castle Gripshom. On the express wish of the king, Christina was raised and trained as a prince and not a princess. At 16, she declined to co-rule with a regency council; instead she took full control at 18 when coming of age.