Nero invented "gay marriage".
You mean this?:
'Same-sex "marriage" was the invention of the Emperor Nero in the first-century A.D. In a comparatively long reign among the first-century Caesars (A.D. 54-68), he began as a talented and generous though youthful friend of the people, but degenerated in a mere 14 years to become the prototype of Lord Acton's axiom: Power corrupts and absolute power corrupts absolutely. Paranoid in his last years, Nero lived in constant fear of assassination as he in turn ordered the assassinations of members of the Senate and nobility, or sent orders to others to commit suicide. Suetonius, a second-century Roman historian, began "to list his follies and crimes," which included at least three same-sex "marriages." Nero's first same-sex "marriage" was preceded by a transgendering operation on his intended bride that was thought to be successful:
Having trued to turn the boy Sporus into a girl by castration, he went through a wedding ceremony with him — dowry, bridal veil and all — which the whole Court attended; then brought him home, and treated him as a wife. He dressed Sporus in the fine clothes normally worn by an Empress and took him in his own litter not only to every Greek assize and fair, but actually through the Street of Images at Rome, kissing him amorously now and then.
Sullivan's assumption that "gay marriage" would require its partners "to live up to the standards of fidelity, responsibility and commitment never before asked of them" is certainly not true in the case of Nero. His infatuation with Sporus did not prevent him from pursuing an incestuous love with his mother, Agrippina; when Court politics moved to block him, he engaged a mistress who looked like his mother, but visual evidence suggested to the onlookers that he and Agrippina had intercourse "every time they rode in the same litter — the state of his clothes when he emerged proved it." Not even his mother was able to satisfy his passion for long; shortly after his "marriage" to Sporus, he "married" a freedman, Doryphyrus, but this time Nero played the bride, "and on the wedding night he imitated the screams and moans of a girl being deflowered." In time, Nero arranged the murders of his mother and his aunt, Domitia Lepida.'
Good grief.
Nero also had a pleasant little practice of dipping Christians in oil, then crucifying them on Vatican Hill, then setting them alight while on the cross. Perhaps this is where the devilish tradition of the flaming cross comes from.