Perhaps the most flagrantly gay European monarch has gone unmentioned so far. This was Gian Gastone, last Medici Grand Duke of Tuscany. He succeeded his tyrannical and overbearingly pious father Cosimo III in 1723, and was immediately popular just for not being his father, who had reigned for 53 years of unrelieved gloom. He earned further popularity by, in a brief burst of energy, enacting modest liberal reforms. It was only brief, though, he soon returned to the spectacularly debauched and indolent lifestyle he had enjoyed before succeeding, and absolutely refused to have anything further to do with the business of government.
Immensely corpulent, he rarely left his bedchamber, or indeed his bed. There he was served vast meals and plied with wine until he passed out. In the meantime, youths picked and paid off the streets would cavort naked or cross-dressed for his entertainment. On the rare occasions when he was persuaded to leave his quarters he would invariably disgrace himself, either being publicly sick or talking loudly and inappropriately. Withal, he remained popular with the people of Tuscany. Why? No ruler could possibly have bothered them less.
He died after a reign of 14 years, and being (obviously) childless was succeeded by the Duke of Lorraine, later Emperor Francis I, who had no conceivable hereditary claim despite some remote Medici blood, but was the beneficiary of a Great Powers stitch-up. His sister Anna Maria Luisa survived another seven years, last of the Medici and revered by all in Florence, and when she died left the entire Medici art collection, of incalculable value and worth, to the people of Tuscany in perpetuity, on condition that it should never be removed from there.