The 79-year-old man sat silently in the back of the courtroom on Long Island, 20 miles from his home in Queens. He wore a dark suit over his slim frame, as if back at his old offices in Manhattan’s financial corridors, at Merrill Lynch and Bank of America and other blue-chip firms.

Here the man, Robin Davis, settled in for what promised to be a strange trial in this mostly empty room. His lawsuit centered on the actions of a person long dead. His adversaries were Long Island bureaucrats who had never heard of that person or his reported misdeeds.

Generations had passed since the terrible acts that Mr. Davis described in his lawsuit, a dark stretch of weeks 68 winters ago, during the first Eisenhower administration. In this courtroom in 2024, he faced lawyers, a judge, a jury of strangers and a ghost who had haunted him for the better part of seven decades.

A ghost who had made him — for good and for bad — what he is today.

Mr. Davis had long been widely known for his philanthropy on behalf of one cause: fighting child abuse. Twenty-five years ago, he created a charity to raise money in the business community to fund boots-on-the-ground agencies in New York City and beyond that sought to treat and prevent the abuse of children.

Now, the trial would reveal the answer to a question about the charity that he’d been asked many times: Why? Why child abuse?

For years, he had come up with reasons. It’s underfunded, he’d say. There’s no poster child for abuse, like there is for childhood disease.