The number of women of color in the US Senate quadrupled Tuesday night, with victories for women in California, Illinois, and Nevada boosting the count from one to four. Here’s how it happened:

Mazie Hirono, a Japanese American who represents Hawaii, was, up until Election Day, the only woman of color in the Senate. Elected in 2012, she became the first and only Asian-American woman senator and the first woman senator from Hawaii.

It was announced relatively early in the night that Democrat Tammy Duckworth, another Asian woman (her mother has Thai and Vietnamese heritage, and her father is white), beat her Republican opponent, Sen. Mark Kirk, in Illinois.

California Attorney General Kamala Harris (D-CA), who identifies as both black and Indian-American, won her race against Loretta Sanchez to take California’s seat. Sanchez is Latina, so this race would have added one woman of color to the Senate’s count regardless of the outcome.

Finally, Catherine Cortez Masto (D-NV), who is Latina, edged out opponent Joe Heck to win in Nevada.

Four is still, of course, a very small number when you consider there are 100 Senate seats. But it’s a significant increase — and the largest leap in any one election.

Women of color candidates still battle bias

These wins didn’t happen in a climate devoid of racial bias. In Duckworth’s case, her opponent sarcastically suggested that her heritage meant her family couldn’t have military history.

Tammy Duckworth is a vet who lost both legs in Iraq. Her family has served since the Revolutionary War. And yet... pic.twitter.com/DHd3kWrUsN — Anthony Breznican (@Breznican) October 28, 2016

When she brought up her family’s long history of serving in the US military at the November event, Kirk said, “I had forgotten that your parents came all the way from Thailand to serve George Washington.” The message he seemed to be sending: Since Duckworth was born in another country, has ancestors from other countries, and is Asian American herself, her family’s long history of service either didn’t exist or wasn’t legitimate. (Kirk later apologized for the remark.)

Watch: The long fight for a female president