A chance encounter decades ago set off the trial that began Tuesday.

Ms. Carroll, a former magazine columnist, said nothing publicly about the encounter for decades before publishing a memoir in 2019 that accused Mr. Trump of attacking her.

In the suit, Ms. Carroll, 79, says that one evening in the mid-1990s, she visited the luxury department store Bergdorf Goodman, where she was a regular shopper. There, the suit says, she ran into Mr. Trump. The two had met at least once before, and they traveled in the same New York City circles, the suit says. He said he was shopping for a present for “a girl,” and he asked her to advise him. She says she eventually accompanied him to the lingerie department where, she contends, he maneuvered her into a dressing room and raped her.

Mr. Trump, 76, has denied that he raped Ms. Carroll, has accused her of lying and has attacked her repeatedly in public statements and on social media, both while in office and after leaving. In 2019, after she published her account, he called her allegation “totally false” and said he could not have raped her because she was not his “type.” Last October, he said again, in a post on Truth Social, that she was not telling the truth and that the case was a “complete con job.”

Shortly before 9 a.m. Tuesday, Ms. Carroll strolled past cameras lined up on Worth Street and entered the courthouse. She took her place in a growing security line next to dozens of potential jurors.

A handful of protesters had gathered. The plaintiff’s supporters chanted “We support E. Jean Carroll” and one held a sign that said “Trump is a rapist.” Another man held a sign with an antisemitic slur calling for the arrest of Reid Hoffman, the co-founder of LinkedIn who has helped fund Ms. Carroll’s lawsuit.

Ms. Carroll’s lawyers will ask the jury to find Mr. Trump liable for battery, and if he is found responsible, to award monetary damages.

Here are some facts about the case:

• The New York State law that allowed Ms. Carroll to bring her suit isn’t even a year old. The Adult Survivors Act, passed in May 2022, allows victims of abuse a one-time opportunity to file civil lawsuits, even if the statute of limitation has run out. Accusers are able to file lawsuits during a 12-month period that started last Nov. 24. Ms. Carroll filed her suit on the first day it was permitted.

• Mr. Trump is not required to attend the trial, and Ms. Carroll’s lawyers have made it clear they do not intend to call him as a witness, the judge noted in a recent order. He could decide to testify in his own defense.

• Judge Lewis Kaplan will lead the process of choosing a jury on Tuesday, posing his own questions to prospective jurors and others submitted by lawyers for both Ms. Carroll and the former president. Ultimately, six to 12 New Yorkers will be selected. Then, opening statements will begin.

Lola Fadulu and Kate Christobek contributed reporting.