Funeral processions are beginning for Tatiana Schlossberg, the late daughter of Caroline Kennedy and Edwin Schlossberg.

Family and friends are gathering at The Church of St. Ignatius of Loyola on New York City’s Upper East Side on Monday, Jan. 5, to mourn following Tatiana’s death at age 35 on Dec. 30.

Extended family members, including Kerry Kennedy and Joe Kennedy III, were among the first to enter the church on Monday afternoon. Her immediate family, including her parents and siblings, Rose and Jack, arrived soon after, as well as her husband, George Moran, and their two young kids, son Edwin and daughter Josephine.

Notable public figures, including late-night veteran David Letterman and Tatiana’s wedding dress designer Carolina Herrera, were also spotted filing into the church, which similarly hosted the 1994 funeral service for Tatiana’s grandmother Jackie Kennedy.

The ceremony was kept private, and police blocked off the surrounding streets.

Tatiana died one month after she announced that she had been diagnosed with acute myeloid leukemia in an essay published by The New Yorker in November. David Remnick, the magazine’s editor, was also among the guests invited to her Monday funeral after praising the strength she displayed in writing about her cancer journey in a statement to PEOPLE days earlier.

The JFK Library Foundation announced the news of her death on Dec. 30 in a post on behalf of Schlossberg’s extended family, saying, “Our beautiful Tatiana passed away this morning. She will always be in our hearts.” The post was signed by “George, Edwin and Josephine Moran, Ed, Caroline, Jack, Rose and Rory.”

Tatiana, who was the granddaughter of former President John F. Kennedy, is survived by her husband and their two children. She also leaves behind her older sister, Rose, and younger brother, Jack, along with her parents.

In her New Yorker essay, Tatiana detailed how she was diagnosed with acute myeloid leukemia after the birth of her daughter in 2024.

“I did not — could not — believe that they were talking about me,” she wrote. “I had swum a mile in the pool the day before, nine months pregnant. I wasn’t sick. I didn’t feel sick. I was actually one of the healthiest people I knew.”

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Tatiana underwent months of medical treatment after her diagnosis, including chemotherapy and a bone-marrow transplant. While she detailed her treatment, she also criticized her cousin, Health and Human Services secretary Robert F. Kennedy Jr., for cutting funding for cancer research, among his many dramatic changes to the agency during his first year in the role.

“I watched from my hospital bed as Bobby, in the face of logic and common sense, was confirmed for the position, despite never having worked in medicine, public health, or the government,” she wrote.

“I watched as Bobby cut nearly a half billion dollars for research into mRNA vaccines, technology that could be used against certain cancers; slashed billions in funding from the National Institutes of Health, the world’s largest sponsor of medical research; and threatened to oust the panel of medical experts charged with recommending preventive cancer screenings,” she added.

Tatiana, who earned a BA in History from Yale and a master’s in American history from the University of Oxford, worked as an environmental journalist and was planning a research project on ocean conservation before her diagnosis.

“My son knows that I am a writer and that I write about our planet. Since I’ve been sick, I remind him a lot, so that he will know that I was not just a sick person,” she wrote in The New Yorker. Of her younger child, she wrote, “I didn’t ever really get to take care of my daughter—I couldn’t change her diaper or give her a bath or feed her, all because of the risk of infection after my transplants. I was gone for almost half of her first year of life.”

She added, “I don’t know who, really, she thinks I am, and whether she will feel or remember, when I am gone, that I am her mother.”

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On the morning of her funeral, the JFK Library Foundation shared a recent photo of Tatiana. The photo, which was taken on Martha’s Vineyard in September, shows Tatiana and Moran with their two children.

“As we remember Tatiana and celebrate her life, our hearts are with her family and all who loved her,” the photo was captioned.