Bagpipers march during the 2015 St Patrick's Day Parade in...

Bagpipers march during the 2015 St Patrick's Day Parade in Manhattan. LGBT activists who have long boycotted the event will march for the first time in this year's parade on Thursday. Credit: AFP/Getty Images / Jewel Samad

The New York City St. Patrick’s Day Parade stepping off Thursday on Fifth Avenue will mark a “day of history and hospitality,” said a leading LGBT activist who will be among the hundreds participating for the first time in the march after years of boycotting.

Parade organizers earlier this month announced they were lifting a long-standing ban on openly gay groups, ending an era of acrimony that began in 1991 when gay and lesbian community members marching with then-Mayor David Dinkins were angrily jeered and pelted with beer.

Brendan Fay, founder of an Irish LGBT advocacy group marching in the parade, Lavender & Green Alliance, said that day changed his life.

Fay said he has been arrested at least a dozen times over the years protesting exclusion at the Manhattan parade. He said Wednesday he is “overjoyed” at the change in policy.

“We have been part of a movement in cultural hospitality,” Fay told Newsday, adding that the parade will be “transformed as we cross a historical threshold.”

About 250 people, including Mayor Bill de Blasio and openly gay City Council members Daniel Dromm and James Van Bramer, will march behind the Lavender & Green Alliance banner.

“It’s a moment where some real healing is happening and some real progress has occurred,” de Blasio said Wednesday at an unrelated lower Manhattan event, “and having watched over this last quarter century with pain . . . it’s amazing when people find a way to overcome divisions.”

The mayor will march twice in the parade, first with NYPD and FDNY members and then with the alliance.

The Fifth Avenue parade, the world’s largest and oldest St. Patrick’s Day march, is in its 255th year. More than 200,000 marchers will participate, including students from Long Island and government officials from Ireland.

The grand marshal will be former Sen. George Mitchell, a key player in the Northern Ireland peace talks of the 1990s.

This year’s parade also celebrates the 100th anniversary of the Easter Rising, when Irish nationalists staged a rebellion against the British and proclaimed Ireland an independent republic.

With Matthew Chayes

Latest video