I find it increasingly curious that, upon reading British history books, every telling of the tragic fall of a monarch seems to come with commentary about how unprecedented it was, how shocking, how cataclysmic. But they weren't entirely ignorant of their own history, even where it was a simple narrative constructed by monks or whatevs. The Anglo-Saxon kings had their fair bit of shenanigans. After Henry I died, Stephen and Matilda pinched the crown off each other a time or two. John told everyone Richard I had died. John himself was pretty much decrowned, and the throne given to the French. Edward II "abdicated" and died in Mysterious Circumstances. Richard II "abdicated" and died in Mysterious Circumstances. Henry VI had his crown pinched, then given back, then pinched again, then died in Mysterious Circumstances. Edward IV had his crown pinched and then took it back. Edward V if not died then disappeared in Mysterious Circumstances. Richard III had his crown taken in battle by one of his subjects. Charles I had his head chopped off. Charles II, to begin with, had no throne to inherit. James II was deposed.
There were a whole host of different circumstances, but the sanctity of the anointed king was surely never completely beyond question. Surely at some point it had to stop coming as a surprise?