Louis XVII would have been King of France after the beheading of his father Louis XVI but for the fact that France was a republic at the time. He died while imprisoned in Paris; or maybe he didn't. The case is puzzling to this day, and conflicting evidence is offered from likely or unlikely sources.
Johan de Witt was Grand Pensionary of Holland, an office with powers similar to that of a Prime Minister cum Foreign Secretary combined. He led the country during the first stadtholder-less time from 1650 to 1672 when Republicans saw their chance to get more power for themselves personally at the expense of the House of Orange.