(Rich von Biberstein/Icon Sportswire via Getty Images)

Lia Thomas became the first known transgender woman to win a Division I national championship on Thursday, winning the 500-yard freestyle in a time of 4:33.24 at the NCAA swimming championships.

Virginia’s Emma Weyant finished second in a time of 4:34.99. Erica Sullivan from Texas took third.

The time was a season best for Thomas, who was a little less than three seconds off of Leah Smith’s pool record of 4:30.81 and more than nine seconds behind Katie Ledecky’s NCAA and American record of 4:24.06. It was four-tenths faster than last year’s winning time, a 4:33.61 posted by Paige Madden of Virginia.

“It means the world to be here,” Thomas said in an interview with Elizabeth Beisel after the race. Thomas declined to attend the NCAA-required post race news conference.

Dueling protests dominated the streets outside of the McAuley Center. Protestors from Save Women’s Sports and Young Women for America stood outside and inside of the pool all day. Their founder, Beth Stelzer, draped a banner with the organization’s phrase over one of the pool’s railings. And while the cheering was loud for each swimmer, it was noticeably quiet during Thomas’ introduction, and reportedly quiet again during the trophy ceremony.

“I try to ignore it as much as I can,” Thomas told Beisel. “I try to focus on my swimming, what I need to do to get ready for my races. And just try to block out everything else.”

Thomas’ participation this season has been under scrutiny since she posted the nation’s top times in the 200 and 500 freestyle in December. She used to compete on the Penn men’s team before transitioning, and this is her first season competing as a woman. Some have argued that she has an unfair advantage, even though Thomas has met all NCAA standards to compete as a woman after undergoing testosterone suppression therapy for over two years.

In February, 16 of her Penn teammates sent a letter to Penn and the Ivy League, urging them to reconsider her eligibility. In it they said that while they “fully support” Thomas in her transition, biologically they felt she has an unfair advantage over her competitors.

Stanford swimmer Brooke Forde, who swam in the 500 freestyle and placed fourth, said in January that she doesn’t have a problem competing against Thomas. On Thursday, Virginia junior Lexi Cuomo said that “any hate is unnecessary.”

“We need to look at it as we’re all competitors right now,” Cuomo said after the Cavaliers won the 200 freestyle relay. “We’re focused on ourselves and our team. Our first and foremost goal is to win a national title.”

Virginia has gotten off to a hot start in their title defense, building an 82-point lead over second-place Texas with 210 points and four event wins.