New members of the most diverse Boston City Council in history were sworn into office at Faneuil Hall Monday, with a majority of members being women and people of color for the first time ever.

Mayor Marty Walsh administered the oath of office simultaneously to the 13 members of the Council as hundreds of supporters and family members looked on.

Walsh offered his congratulations and onlookers answered with a round of applause when he referred to highlights of Boston's November election.

“We elected our first Afro-Latina, an immigrant of color. But don't sit down,” he said, before he lauded the newly-formed female majority on the Boston City Council. "You might as well stay standing."

A significant presence at the ceremony was Julia Mejia, who won the final at-large seat by just one vote after defeating Alejandra St. Guillen in a December recount. The Council is now made up of seven women and six men.

The Council elected Councilwoman Kim Janey, who represents District Seven, which covers Roxbury and portions of Dorchester, the South End and Fenway, as its new president.

Janey said she is proud to be part of the most diverse Council in Boston's history and that will inform her agenda.

“There is no better way to begin this term and the new decade by working with all of you, to create a more inclusive and equitable Boston for all,” she said.

Janey said she will prioritize eliminating racial disparities in Boston's schools, increasing affordable housing and to reconsider the idea of free MBTA bus service.

“Let’s find new ways to tackle old problems,” she said.