Mathilde Krim died yesterday, at age 91. In 1983, she founded the AIDS Medical Foundation (AMF), the first private organization working in AIDS research and advocacy, which merged with The American Foundation for AIDS Research (amfAR) in 1985.

Krim began her career as a scientist. She grew up in Geneva, where her father worked in public health, and studied biology in college over her parents’ objections. During the war, when she was in school, she worked part-time as a clerk for a Jewish lawyer who advocated—mostly unsuccessfully—for Swiss visas for Jewish refugees from Nazi-occupied countries. According to the Jewish Women’s Archive, Krim’s parents were reluctant to believe that the Holocaust was real, but while at the movies in 1945, Krim saw a newsreel about the liberation of the death camps that solidified her support for Jews. In school, she became friendly with some Middle Eastern Jewish students, became fascinated with Jewish history, and got involved with underground gunrunning. In 1948, just after the founding of the State of Israel, she converted to Judaism and married David Danon, a fellow student and member of the Irgun. Her parents disowned her.

In 1951 she had a daughter, Daphna, and in 1953 she got her PhD (she was one of the first people to use the electron microscope to study the double helix of DNA) and moved to Israel. Sadly, her marriage failed, and she took a job as a researcher at the Weizmann Institute. Her work with Leo Sachs led to the development of amniocentesis.

In 1957, she met and fell in love with Arthur Krim, the head of United Artists and later Orion Pictures, who was a Weizmann trustee. They married and tried to have a long-distance Rehovot-NYC relationship, which proved untenable; Mathilde and Daphna moved to the Upper East Side in 1959. Mathilde and Arthur were active in the American civil rights movement, and in the fight for Zimbabwe’s and South Africa’s independence. She also continued her scientific research, first at Cornell Medical College and then at Sloan-Kettering. During the course of her career she published over 60 scientific papers.

In 1983, she began seeing patients with a rare skin cancer, Kaposi’s sarcoma. Soon she was swept up in AIDS research and furious about the public’s and government’s reluctance to fully address it; that’s why she started her foundation. “I was incensed!” she told The New York Times in 1984. “So many young men were dying, mostly intelligent and sophisticated young men… and many would be dying abandoned or alone because they were afraid to contact their families.”

Eventually she realized she could accomplish more with her fundraising connections than in a lab. She tapped into her husband’s network and built up amfAR’s board and image with glittering celebrities and society folks, most notably Elizabeth Taylor. She herself looked like a perfect society lady, in her elegant pearls, with a spun-sugar helmet of honey-colored hair.

But her mild appearance was deceiving, noted Jay Blotcher of Public Impact PR, who was Director of Media Relations at amfAR from 1995 to 1999. “She was steel wrapped in velvet,” he said in an interview. “She had such firm resolve, but such Old-World European elegance; if you crossed her, you’d know it. She did not mince words, but she was also diplomatic to the max.”

She was also fierce in her beliefs. “AmfAR was perceived as a very mainstream organization, but she should be remembered for taking a stand early on for needle exchange, which wasn’t a popular position when we labored under the idiocy of the so-called War on Drugs,” Blotcher said. “To its credit, amfAR heeded medical research, not politics. Clean needles minimize transmission. Dr Krim never backed down. She was a powerhouse.” Blotcher paused. “She brought out the best in all of us,” he continued, “because she was so exacting about what she called on herself to do. She expected that level of service and sacrifice from others. She was a realist as well–more than once, she’d be candid and say she was uneasy about AmfAR having to rely on gilded events to keep their agenda going. She’d say that celebrities were a necessary evil. Their involvement got people to open their pocketbooks. Mostly I remember how gracious she was–she always thanked people, in that Swiss accent.”

She was also a mensch behind the scenes, when no one could see. “Back in 1996, we were tasked with saving the Office of AIDS Research, a government organization that was in danger of being closed down,” Blotcher recalled. “AmfAR went to various states where people were on committees that would decide the office’s fate. When we went to Oklahoma City, she said, ‘Before we start our day, we have to go to the site of the bombing to pay our respects.’ That was a priority for her. There was no one else there, just her and me. She stood quietly in front of all these stuffed animals. It really exemplified her humanity.”

She was awarded 16 honorary degrees; in 2000, Bill Clinton awarded her the Presidential Medal of Freedom for her “extraordinary compassion and commitment” to AIDS patients and research.

No one seems to have had anything bad to say about her. Not even Larry Kramer! After Krim recommended a candidate for Health Commissioner to David Dinkins in 1990, a man who turned out to have advocated keeping records of the names of anyone with HIV or AIDS, Kramer said, “We are all very angry with her…so far as one can ever get angry with Mathilde, because we love her so.”

When her death was announced this morning, NYC city council speaker Corey Johnson posted on Facebook, “As an HIV positive man who has been living with the virus for over 13 years, I know that I would not be alive today without the efforts of Dr. Mathilde Krim. I met her during my first trip to New York City, at age 18. Little did I know the important role she would play in my life…Her legacy will live on in the countless lives she saved.”

Candida Scott Piel, the community liaison at amfAR from 1994 to 2002, recalled in an interview, “I did various fundraisers for amfAR, including the Mr. Leather contest. In 1995, the winner was Andy Borden, a tall, handsome, lovely guy. Arthur Krim had recently died, and Dr. Krim was pretty low. I thought, ‘She should come meet Mr. Leather! This might be fun!’ I introduced them, and it was like the rest of us just disappeared. They fell madly in love with each other and it was the sweetest thing in the world. They had coffee, and the photographer Morgan Gwenwald got a photo in which Dr. Krim climbed a library ladder to be in a shot with Mr. Leather, because he was like six-foot-seven. They adored each other. When amfAR was participating in the 1995 Pride Parade, we thought it wouldn’t be dignified for Dr. Krim to be on a float, but maybe she could ride in a Jeep? The prospect of riding down Fifth Avenue in the back of a Jeep with Mr Leather…she was all in. It was a match made in heaven and a delightful fluke.”

Jewish tradition holds that dying on one’s birthday is an indication of someone’s righteousness. “On the day we are born we are entrusted with a mission,” the Lubavitcher Rebbe once said. “The righteous person lives his life achieving his fullest potential and completes his mission on earth in the most perfect way possible. This perfection is expressed in the fact that his mission ends on the very same day that it was begun.” The fact that Krim died, not on her own birthday, but on the birthday of a great civil rights leader, seems momentous too.