A toaster.
I thought that was only if I ‘converted’ to homosexuality.
Back to the OP. So, someone who voluntarily came out of the closet? So, Oscar Wilde is out, right? Anyone who actually said openly in history of mankind that they were gay?
How about Marbod or Baudri of Bourgueil?
He’s the earliest person I can think of who was in the gays, got sent to jail for it, and emerged with his reputation and legacy intact, and indeed enhanced. The monde that Wilde inhabited was only acceptable in certain circles at the time, but he paved the way for the “nod and a wink” mainstream public acceptance of homosexuality. Everyone who cared to think about it knew that Noel Coward was only nominally a ladies man, but he made several films as a war hero, and that was accepted at the time. From Coward onwards, there have been many, many homosexual British entertainers, working at the level of “camp” mostly, but mainstream.
It’s a meaningless question, because attitudes to sex have changed so wildly over the years. For instance, the Duke of Buckingham was supposed to be the King’s lover. In Rome, if you were a man, it didn’t matter which sex you shagged, as long as you were the one doing the penetrating. In Classical Greece, it was more mutual frottaging than penetration, and was seen as entirely normal.
Hrm… new word of the day, for me.
Maybe Otzi could be considered for this honor - though Cecil seems to disagree.
Famous Florentine 16th-c painter Giovanni Antonio Bazzi, nicknamed il Sodoma and proud of it, might be a good option (my favorite self portrait here. ). We have records of his fabulous parties, he had this menagerie of odd animals around his studios and property (swans, badgers, you name it), and seems to have just been in general an interesting character. Good stories in Vasari, but the Wikipedia article on him seems pretty expurgated (drawn from an ancient bowdlerizing encyclopedia).
As an alternative to Wilde, what about Magnus Hirschfeld, who wasn’t only openly gay as early as 1897, but was a gay activist, and was one of the founders of the first gay rights organization (The Scientific Humanitarian Committee).
This is really an aside, since it was evidently a case of transgender rather than homosexuality per se, but perhaps the Chevalier d’Eon deserves to be mentioned here.
It’s a toaster oven.
His teachings, most generally his encouraging the young to question their elders, both figuratively and literally. (Don’t they usually do that anyway, though?) The homosexuality didn’t enter into it–the sort of encounters he engaged in were common and accepted in ancient Greece. I’d actually question counting Socrates in your list of homosexuals, in fact. He was happily married with several children, and his dalliance with boys were the typical means by which ancient Greek gentlemen relieved their sexual urges when they weren’t interested in making babies. There’s no reason to think that his sexual focus was on other males; this was just the 200 B.C. version of masturbating to porn videos on the Internet.
Plato was queer as a three-dollar bill, though. 
So Plato was (were) more than one person?
Isn’t it time we started giving microwaves? Maybe a convection oven combo.
Well, in the Bible there is David & Jonathan (“surpassing the love of women”), which is dated to around 1000-1050 BC.
About a thousand years earlier, circa ~2650 BC, there is the story of Gilgamesh and Enkidu in the Epic of Gilgamesh. Since that’s from the Bronze Age, and one of the oldest written works to have survived, I don’t think you could get much earlier than that.
I read the Epic of Gilgamesh. The wildman Enkidu is first brought out of the wilderness when he’s seduced by the harlot Shamhat. He and Gilgamesh become best buddies, but I don’t remember any part about Gil and Enkidu getting it on, Babylonian style.
Only in alterno-world. His wife divorced him, his sons were given a different family name, and his plays were never performed again in London during his lifetime. He left prison in disgrace, and died an alcoholic expatriot in Paris.
If only fictional characters counted. Achilles and Patrocles were pretty indisputably lovers, much more clearly than Gil and Enk, or Dave and Jon.
it’s been 30 years since I’ve read it, but I remember one of them growing his hair long and dresssing like a woman, and mourning “as for a wife” when the other one died.
Well, a few candidates for the list, depending on how you choose to define “gay” in terms of anachronistic usages:
Edward II, King of England – made no secret of his preference for Piers Gaveston and, later, the younger Hugh Despenser, although married to Isabelle de France for diplomatic/political and heir-begetting reasons.
Richard I the Lionhearted, King of England – supposedly an open secret that his tastes ran to men, although he did contract a childless (and apocryphally unconsummated) marriage to Berengaria of Navarre.
William II Rufus, King of England – the Conqueror’s son likewise had a reputation as having a taste for male/male sex.
Hadrian, Emperor of Rome – the love of his life was Alcinoos, who drowned in the Nile and for whom he grieved. I’ve never been able to re-pin down a reference I once saw to them actually contracting marriage.
Alexander II the Great, King of Macedonia – apparently he liked sex of any sort but preferred it with men or adolescent boys.
Amenhotep IV (Akhnaten), Pharaoh of Egypt – the great monotheistic reformer was evidently bisexual, the two deep loves of his life being his queen Nefertiti and his half-brother and lover Smenkhkare.
If we’re going to go down that path, Catalina de Erauso (link in Spanish), called “la monja alférez” (the ensign nun) was raised in a convent, escaped it, joined the army, made lieutenant, almost got married to a woman, was later made ensign by the king “in reward for her services to Us” (get your mind out of the gutter, it wasn’t that kind of services!).