September 5, 1638 - September 1, 1715: Age 66
Louis XIV of France, also known as The Sun King, began feeling unwell in early 1715. As King of France, a great superpower, at 66 he was arguably the most powerful man in the world. Various diagnoses and treatments didn't improve the situation and by early August he began to experience severe pain in his leg. By late August he was diagnosed with gangrene and ordered to bathe his leg in burgundy and ass's milk. Two days later the doctors were recommending incisions but, knowing he was going to die anyway, Louis refused. He asked how much time he had: it was a Monday, and the doctor replied "Sire, we may hope until Wednesday." In fact Louis lived until the following Sunday.
Needless to say his last days were not pleasant, but they were made worse by the intrigues that flowed around him. In the previous few years, Louis XIV lost nearly all of his legitimate heirs: his son, two grandsons, his brother, and two great-grandsons. He was succeeded by his youngest great-grandson, Louis XV, who was 5 when he died, and whoever served as Regent would have many years to mold the new young King and place his friends and relations in positions of importance. (His wife, Madame de Maintenon, bullied him into naming her favourite as Regent.)
He spent his last days saying goodbye and giving last minute advice. In response to the weeping and wailing going on around him, at one point he said, "Why do you weep — did you imagine that I was immortal?" At the end, he was left to the priests and his room was filled with religious music and prayers. On 1 September he died.
Source: Mitford, Nancy, The Sun King, 1966.