BOSTON (AP) — Democrat Michelle Wu has emerged the top vote-getter in a runoff election for the next mayor of Boston, but the race to decide her opponent in November remained too early to call early Wednesday.

Wu, a city councilor, easily won Tuesday’s preliminary balloting, with fellow councilor Annissa Essaibi George trailing in second. Two other candidates — acting mayor Kim Janey and fellow city councilor Andrea Campbell — both conceded defeat late Tuesday night.

All four are candidates of color, as is John Barros, Boston’s former economic development chief and the only man in contention. Barros trailed well behind the four women.

No matter who joins Wu on the Nov. 2 ballot, history has already been made in a city that has never elected a woman, Black resident or Asian American as mayor. For the past 200 years, the office has been held by white men.

Wu and Tuesday's other winner will face off against each other on Nov. 2, ushering in a new era for the city which has wrestled with racial and ethnic strife.

Earlier this year, Janey became the first Black Bostonian and first woman to occupy the city’s top office in an acting capacity after former Mayor Marty Walsh stepped down to become President Joe Biden’s labor secretary.

“I want to congratulate Michelle Wu and Annissa Essaibi-George on their victories this evening," Janey said in a statement. “This was a spirited and historic race, and I wish them both luck in the final election.”

All of the candidates are Democrats. Mayoral races in Boston do not include party primaries.

The candidates hail from a range of backgrounds. Wu’s parents immigrated to the United States from Taiwan. Janey and Campbell are Black. Essaibi George describes herself as a first generation Arab-Polish American. Barros is of Cape Verdean descent.

Wu, who grew up in Chicago and moved to Boston to attend Harvard University and Harvard Law School, is the only candidate who wasn’t born in the city.

Boston has changed radically since the 1970s, when the city found itself in the national spotlight over the turmoil brought on by school desegregation, and in the late 1980s, when the case of Charles Stuart again inflamed simmering racial tensions.

Stuart is believed to have shot and killed his pregnant wife in 1989 while trying to blame the killing on an unknown Black man, prompting police to search Black neighborhoods in vain for a suspect. Stuart later jumped to his death from a bridge.

The latest U.S. Census statistics show residents who identify as white make up 44.6% of the population compared to Black residents (19.1%), Latino residents (18.7%) and residents of Asian descent (11.2%).

The city has also changed politically.

In 2018, former Boston City Councilor Ayanna Pressley defeated longtime Democratic U.S. Rep. Michael Capuano to become the first Black woman elected to Congress from Massachusetts. That same year, Rachael Rollins, a former federal prosecutor, won election to become Boston’s first female district attorney and the first woman of color to hold such a job anywhere in Massachusetts. In July, she was nominated by Biden to become the state’s top federal prosecutor.

Among the challenges facing the city are those brought on by gentrification, which has forced out many long-term residents, including those in historically Black neighborhoods.

Added to that are a host of other challenges that will face the new mayor, from transportation woes, racial injustice and policing to schools and the ongoing response to the COVID-19 pandemic. One of the most pressing issues is the cost of housing, which is outpacing the financial means of many tenants and prospective homeowners.

There have been moments of controversy during the campaign.

Janey was faulted for invoking slavery and lies about Barack Obama’s citizenship pushed by Donald Trump when discussing New York’s effort to require people to prove they’ve been vaccinated before entering indoor public settings.

She later walked back the comparisons, saying “I wish I had not used those analogies.”

Essaibi George has also found herself under scrutiny after The Boston Globe reported her city council office tried to undermine a building project that would have blocked the view of a luxury condominium building owned by her husband.

Essaibi George later said her husband’s name never came up in the municipal hearings and she only became aware of his involvement after being quizzed by reporters.

The contest was also the first preliminary election in the city’s history to allow mail-in voting, and it had allowed for early voting last week.