One of Boston's most iconic events, the South Boston St. Patrick's Day Parade, broke away from the past Sunday.

Twenty years ago, the U.S. Supreme Court ruled parade organizers had a constitutional right to exclude gay groups. This weekend they chose for the first time not to exercise that right, and openly gay participants marched alongside others. The change was tough to see, but made a difference for many.

Although it was called a historic day by many, Sunday's parade was relatively anticlimatic and little different from previous years, apart from the markedly thinner crowds and an adjusted parade route because of the snow. The first gay group parade organizers accepted — the veterans organization OUTVETS — marched in matching blue jackets and smart white gloves, behind a large banner and smiling 6th District Congressman Seth Moulton. Spectators greeted them as warmly as other groups.

Those in the crowd said the big change this year was emotional. Annie Gazero of Framingham said the inclusion of gay groups made her feel better about attending.

"I'm all for it," she said. "I think they belong here and I don't see why there'd be any kind of objection at all."

That sentiment was echoed among a cross-section of parade goers. And while the crowd seemed happy to have the openly gay marchers included, at least three Catholic groups objected. In a statement, the Catholic Action League of Massachusetts called for the name "St Patrick" to be removed from the parade's title. The League's Executive Director, C.J. Doyle, said the gay groups "promote an ideology which is antithetical to Catholicism." The Immaculate Heart of Mary School from the town of Harvard pulled out of the parade after participating for 25 years. A post on the school's Facebook page said they were "defending the honor of St. Patrick." Also boycotting was the Massachusetts State Council of the Knights of Columbus, which said the parade had become, “politicized and divisive."

Meanwhile, the second and larger gay group accepted by parade organizers, Boston Pride, was very careful to abide by parade rules banning political messages. Their 20-member delegation mixed few rainbows in with their St. Patrick's Day green. Only their relatively small white banner distinguished them from other groups as openly gay. To some extent that was because they were accepted on such short notice. But it was also by design.

"Our goal is not to make a gay parade here," said Sylvain Bruni, Boston Pride's president. "So it's not about putting out any signs or specific message other than, you know, there are members of the LGBT community that do belong here and want to celebrate today and we need to have a space for them."

Another Boston Pride marcher, lifelong Boston resident Anna Dubrowski, said she never cared about being in the St. Patrick's Day parade before. She always associated it with drunken boorishness.

"A lot of people who live in South Boston usually took off or whatever — because it wasn't exactly one of the parades you want to be in, you know what I mean?" Dubrowski said. "So even if I were Irish, I probably would not come here. The reason we're here now in the parade is for the reason so we can be included."

Dubrowski said joining the parade feels like gay groups are joining the mainstream fold. She says she doesn't hold a grudge for being excluded for so long.

"This has always been a black eye to Boston," she said. "So I'm glad that it's changing."

Dubrowski says she's happy South Boston's iconic event now reflects the inclusiveness and acceptance she feels in the rest of the city.