There are rumours that Tsar Alexander I did not die at the official death date and retreated to Siberia where he became a monk.
Achdke Johann Salvador of Tuscany disapeered while sailing near Cap Horn and his body was never found.
The body of King D.Sebastião of Portugal was never recovered after the disaterous battle of Alcácer-Kibir in Morocco, which produced the appearance of several fake kings, most of which were immediately killed, but one of them, feared to be the real one, was imprisionned by Felipe II in Naples.
What are notable examples of royals who disappeared, or are rumored to have disappeared? Whose bodies were never found, or whose corpses are rumored to be missing from coffins, or have been replaced by body doubles?
The reason for my asking is that until recently, I hadn't heard anything about the end of King Ludwig II of Bavaria, other than that his dead body (along with that of his doctor, Bernhard von Gudden) was found in Lake Starnberg. The official version of his death was that he murdered his doctor, and then immediately afterward took his own life by drowning -- notwithstanding the fact that his body was found in waist-deep water, and no water was found in his lungs.
However, I've actually heard bizarre theories that he somehow managed to escape that fateful night (June 13, 1886) -- to God knows where. That he disappeared, and that his coffin is empty (notwithstanding the photos taken of him lying inside, presumably doctored) ... That if there is a corpse, it's not his at all, but rather some body double ...
Of course, I don't buy any of it: there should be plenty of other persons in royal history with more plausible stories of escape or disappearance.
I'm not sure if I totally buy the official version of Mad Ludwig's ending, however. Indeed, I've often wondered why it was that, if he suicided by drowning, he was able to receive a religious funeral and burial services in accordance with the rites of the Catholic Church. After all, back in those days, she was far more stringent in the stance against suicide: people who took their own lives were generally denied funeral masses, not to mention burial in consecrated grounds.
Look what happened less than three years later, when the king's Austrian cousin (Crown Prince Rudolf) died by his own hand: all efforts had to be expended, to cover it up; and all campaigns had to be stretched, to permit him a religious funeral and burial services.