What would happen to him?

[JMISBEST]

Theirs something I've wanted to know for a while, can you help?. Please and thank you

If a King has identical twins, dies 20 odd years later and then 10 years after that its proven that due to a mistake the younger and not the older twin ended up king what would happen to the 1 that became king even though he had no right to be yet it wasn't his fault, it was simply a mistake made by person doing the paperwork with the kingdoms register of births?

 

[Sigtrygg]

Once you are anointed king you are king - unless it is a constitutional monarchy and the parliament/senate/congress/moot can vote for your removal.

The legitimate claimant can either hope his older brother abdicates in his favour or would have to resort to illegal means - alternatively go and have an iron mask made and find an old asteroid base somewhere....