NEW YORK — George Mitchell, a former U.S. senator from Maine who helped negotiate the 1998 Northern Ireland peace accord, participated in the annual St. Patrick’s Day parade in New York City today, agreeing to serve as grand marshal after organizers opened the event up to all openly LGBT marchers.

Mitchell, 82, who oversaw negotiations that led to the 1998 Good Friday Peace Agreement in Northern Ireland, won the Presidential Medal of Freedom and the Liberty Medal. He served in the Senate from 1980 until 1995 and was later U.S. special envoy for Northern Ireland and then for Middle East peace.

“Peace, openness, inclusion, let’s all work together for a better future for people, Irish-Americans, all Americans, all people,” said Mitchell before the start of the parade.

For years, organizers excluded LGBT groups from marching under banners identifying their sexual orientation, drawing the ire of critics who said the policy amounted to discrimination. This year, the Lavender and Green Alliance, an Irish-American LGBT organization, joined the procession along with marchers from a small LGBT group affiliated with the parade’s television sponsor, which first participated in 2015.

The 255th edition of New York City’s parade was expected to draw more than 2 million spectators and 200,000 marchers, including more than 100 bands.

Festive parade-goers donned large shamrock hats, glitter sunglasses and even entire suits made of green.

“I’m Irish born, so it means a lot,” said parade-goer Patrick Ferry. “It’s my heritage, it’s St. Patrick’s Day, my name’s Patrick.”

“It’s my 50th birthday,” said Sean McLellan. “There’s 12 of us here from Scotland, Dundee in Scotland. We’re having a ball celebrating my 50th.”

“Pipe bands, because that’s really Irish,” said Jackie Hall, when asked what her favorite part of the parade was.

This year’s event honors the 100th anniversary of the Easter Rising, the armed uprising during Easter Week of 1916 that led to Ireland’s independence.