Sunday’s mass murder in Orlando, Fla., was, among other grim superlatives, the worst instance of anti-gay violence in American history. But it was also far from the first. In fact, mass violence and the history of gay liberation go hand in hand.

Until the weekend’s horrific shooting, the largest massacre of gay people was an arson attack on a bar in New Orleans on June 24, 1973. Like the community that gathered at the Pulse nightclub in Orlando, L.G.B.T. people had piled into the UpStairs Lounge on the edge of the French Quarter for a happy hour to celebrate the fourth anniversary of the Stonewall uprising. Most of the patrons left after the celebration ended, but congregants of the local chapter of the Metropolitan Community Church, a national gay religious organization, remained.

Just before 8 p.m., someone, or possibly a group of people, stopped at the entrance to the stairwell to the UpStairs Lounge, which was on the second floor of a building that had a straight bar on the first floor and a flophouse on the third. They doused the stairwell with lighter fluid, as well as the steps leading to the second floor, and then lit it. Then they rang the doorbell. When one of the patrons opened the locked door, fire exploded into the room. Within seconds, it spread through the bar, the power went out and the room filled with black smoke. The windows were barricaded and the congregants could not find their way to an exit in the back of the bar.

Thirty-two people died, and many others were injured. Many of the people who died were unidentifiable, not only because the fire scorched their bodies, but also because, despite the celebration of gay liberation, many gay men were not out of the closet and used fake IDs and aliases in gay bars. Even their families didn’t know they were there.

The UpStairs Lounge was not the only target of mass violence during the height of gay liberation in the 1970s. Arsonists set fire to gay churches in Los Angeles, Santa Monica, Nashville and San Francisco in 1973 and 1974. Six months before the fire at the UpStairs Lounge, on Jan. 27, 1973, a fire broke out at the “Mother Church” of the M.C.C., in Los Angeles, where a gay Jewish group met for services. ...