Longer reign than Elizabeth II had more rulers in the history of mankind, just the accuracy of the days is not known. I have written here before that the ancient Korean king Jangsu ruled for 78 years, in the years 413-491, which is historically verified. We know that he ruled for approx 78 years, but we don't know if it was 78 years and 2 months or 78 years and 8 months, etc. Such detailed records were not kept or preserved. It is not right to ignore long-live ancient and medieval rulers because of this. In order, Elizabeth II she surely overcame Jangsu, she would have to rule 79 years, by 2031, which is unrealistic given her age, she would be almost 105 years old in that year. And even that might not be enough. King Minhti of Arakan (now part of Myanmar) allegedly ruled for 95 years between 1279 and 1374. We possible will never know for sure who was the longest reigning sovereign monarch in history, but it is certainly not Louis XIV.