Can any royal wedding go off without a hitch? Just days before Prince Harry and Meghan Markle's wedding, for instance, the father of the bride decided he wouldn't attend the highly anticipated event. He made that choice after he suffered a heart attack and after his staged photo scheme was revealed, saying he wouldn't want to embarrass the British royal family further. (You know those photos of Thomas Markle reading a book called Images of Britain? All a hoax!)

But that flap pales in comparison to some of the royal wedding scandals on this list, controversies from the United Kingdom and beyond. Multiple monarchs, for example, have had to step down from the throne or step out of the line of succession because of their choice of spouse. Another one married a man with ties to the Nazi Party. And another married a woman with ties to a drug kingpin. But we'll start with the drama surrounding the weddings of Prince Harry's father and brother…