For the first time since taking office in 2014, Mayor Bill de Blasio took part in this year's St. Patrick's Day parade up Fifth Avenue after the parade's organizers dropped their longstanding ban on LGBT groups. NY1's Bobby Cuza filed the following report.

It's a 255-year-old event, but never before had the St. Patrick's Day parade seen LGBT groups marching under their own banner, groups that until this year had been banned.

"Today is all about LGBT people being able to claim all of who they are," said Marianne Duddy-Burke of DignityUSA.

"Inclusion matters. Equality matters. Our cultural celebrations need to be more welcoming and inclusive," said Brendan Fay of the Lavender and Green Alliance.

Including himself this year was Mayor Bill de Blasio, who ended his boycott of the parade, taking part in the full day-long slate of events: hosting breakfast at Gracie Mansion, attending mass at St. Patrick's Cathedral and then walking the parade route several times, with police officers in the morning and then again alongside LGBT groups in the afternoon.

"Today, everyone is celebrating together. Today, the city is at peace. The city is unified," de Blasio said.

De Blasio isn't the only one who's boycotted this parade in the past. A number of other city officials were also making their first official appearance this year. That included City Council Speaker Melissa Mark-Viverito, who ended her boycott and led an official contingent that included several openly gay Council members.

"The last time I stepped on Fifth Avenue was 16 years ago today. I was promptly arrested and put in jail for 24 hours overnight because I wanted to march in this parade as both an Irish-American and as a gay man," said City Councilman Jimmy Van Bramer of Queens.

"Today, lesbian, gay, bisexual, transgender people are marching. Straight people are marching. Protestants are marching. Catholics are marching. This is the true spirit of Ireland."

Controversy over the ban stretched back decades. Last year, organizers allowed one LGBT group to march, but the mayor didn't believe that went far enough.

While his boycott undoubtedly added pressure, the mayor credited many others, among them Cardinal Timothy Dolan, for helping get the ban get lifted completely and sending a powerful message.

"I think it sends a moral signal more than a political signal," de Blasio said. "I think this says that New York City is whole again, that the people in New York City are unified, and that we're learning to overcome divisions."