Edith Lees Ellis, 1861-1916 socialist, feminist and writer, was the wife of Havelock Ellis, the sexologist.
Her birthday is not recorded anywhere I can find it, so today is a random and arbitrary attribution.
Edith was a member of the Fabian society and wrote regularly for The Freewoman.
Havelock characterised her relationships with women as lesbian. I suppose this makes her the first ‘official’ lesbian.
There is some argument that Havelock was trying to make out it was his idea that she be a lesbian (when in fact her relationships were all a-sexual) even though her relationships with women predate their meeting; or that he was using this to justify their lack of a sexual relationship. She does not appear to have ever had sex with her husband, they often lived apart and kept separate finances.
I find myself supremely unconcerned about whether she consummated any relationships: her strongest emotional relationships were with women.