PHILADELPHIA (AP) – Forty years ago, a group of men and women in their Sunday finest staged a daring Fourth of July protest in front of Independence Hall in support of gay rights. Except for a few hoots and hollers, they were left alone.

Philadelphia, birthplace of the U.S. Constitution – and the country’s gay rights movement?

The 1965 demonstration came four years before the Stonewall Riots in New York City, considered by many to have launched the equal rights movement for gays.

“Without the demonstrations, Stonewall would have not taken place. We created the mindset for the expression of dissent,” said Frank Kameny, 79, one of the organizers of the earlier event.

Philadelphia-based Equality Forum agrees. The group is planning a May 1 celebration in front of Independence Hall to honor 40 leaders of the gay rights movement. New Hampshire Bishop V. Gene Robinson, the Episcopal Church’s first openly gay bishop, will lead an interfaith service.

The location for the 1965 demonstration was chosen by leaders of the Mattachine Society, a support group for gays, Kameny said. Protests were held for four more years at the same site, until New York’s first Pride parade in 1970.

The Pennsylvania Historical and Museum Commission has approved a state historical marker near Independence Hall declaring the area the site of the first public demonstration for gay and lesbian rights.

But not everyone agrees on the significance of the event.

Historian John De Cecco says the 1969 Stonewall riot – which started when patrons of a gay bar in New York City’s Greenwich Village fought back in a police raid – sparked the gay rights movement.

“That’s the most favored date,” said De Cecco, 80, a retired San Francisco State University professor and editor of the Journal of Homosexuality.

Historian Martin Duberman, author of Stonewall, said neither of the ’60s events truly owns bragging rights. He said the movement dates to a group formed in the 1920s.

“There’s enough credit to go around on this. There’s no need to claim that ‘we were the first, or the best or the greatest,’” said Duberman, a professor at Lehman College in New York.