The cruise ship Celebrity Summit, photographed from High Head in North Truro, sits off Provincetown Harbor. The ship arrived early Thursday, with some on board carrying parts of an LGBTQ rainbow flag for a beach ceremony ahead of Carnival week in town. [Merrily Cassidy/Cape Cod Times] ▲ Gilbert Baker's 25th anniversary rainbow flag reaches more than mile down Duval Street in Key West, Fla., in 2003. A section of the flag has been brought to Provincetown by the Provincetown Business Guild as part of the Carnival celebrations. [Courtesy of the Provincetown Business Guild] ▲

PROVINCETOWN — The sight of a large cruise ship in the low-profile harbor early Thursday heralded an early start to the town's Carnival week festivities.

At a ceremony on the beach Thursday morning, cruise officials and the town's LGBTQ supporters gathered to celebrate the origins of the rainbow flag, first stitched by Gilbert Baker in San Francisco in 1978. Following the death of gay rights activist Harvey Milk in that same year, Baker went on to stitch many more rainbow flags including a 25th anniversary one, in 2003, called the Gilbert Baker Rainbow25 Sea to Sea flag.

Baker, who died two years ago, originally designed the flag with eight colors but modified it to the six strips of color — red, orange, yellow, green, blue, and violet — typically seen now as a symbol of the LGBTQ rights movement.

Sections of Baker's 25th anniversary flag will be on display during Carnival week, some brought to town aboard the cruise ship Celebrity Summit.

"It's an honor to host it in Provincetown," said Robert Sanborn, executive director of the Provincetown Business Guild, who described the flag as a tangible piece of gay rights history.

The guild, which promotes LGBTQ tourism, is hosting the flag in cooperation with the Stonewall National Museum and Archives in Fort Lauderdale, Florida, and the Key West Business Guild in Key West, Florida.

"It's the 50th anniversary of the Stonewall riots," Provincetown tourism director Anthony Fuccillo said, referring to rioting outside the Stonewall Inn in New York that is seen as a spark for the modern gay rights movement.

"This year is very important to everyone in the LGBTQ community," Fucillo said. "It's important that Provincetown show that support."

Vacaya, a new LGBTQ vacation company, arranged the cruise to Provincetown. The ship, built to carry 2,218 people, arrived at 3 a.m. Thursday and is set to depart Friday evening.

— Follow Mary Ann Bragg on Twitter: @maryannbraggCCT.