During the Forest Fair, an annual Girdwood summer festival that celebrates tie-dye, home-spun crafts and public hula-hooping, signs posted on the tall trees alert visitors to three main rules: "No dogs, no politics, no religious orders."

But one of those rules, a doctrine of the fair for more than four decades, now faces a legal challenge. Last week, two evangelical Christians, one of whom is a well-known activist, filed a lawsuit in federal court saying the ban on "religious orders" infringes on their constitutional right to free speech.

The lawsuit is a constitutional test for a far-flung neighborhood of Anchorage that feels like its own town, and prides itself on a freethinking, laid-back culture. The suit, which comes from a religious activist, also raises questions about the difference between a public and private event.

David Grisham — who, in December 2016, gained national attention for telling Texas children waiting in line for Christmas photos that Santa didn't exist — and his stepdaughter, Texas resident Tina Watson, say in the suit they were halted from distributing religious leaflets at the festival in July. They say they should be allowed to pass out leaflets because the event was advertised as free and open to the public. Grisham also claimed he was assaulted by security guards and dragged away from the center of the park, where he was passing out Christian literature.

In a letter to Grisham's attorney last year, Anchorage assistant city attorney Todd Sherwood said that while the event was free and open to the public, organizers of the Forest Fair, a nonprofit organization, had an exclusive permit to use the park for their own purposes. The organizers chose to have rules and conditions for invitees, Sherwood said. He likened the process to reserving the park for a wedding.

Sherwood's letter also said that Grisham was the one who was being aggressive. The city didn't immediately have additional comment on the lawsuit.

It's not the first time someone has protested the "no religious orders" rule, which dates back almost to the dawn of the festival in 1974, said Tommy O'Malley, a longtime organizer of the fair and former member of the Girdwood Board of Supervisors.

But O'Malley said it's the first time he's aware of the issue going to court.

"To take a vacation from that kind of stuff, actually, we said 'no religious orders,'" O'Malley said. "That's from 41 years ago."

The lawsuit names the municipality of Anchorage as a defendant, as well as parks director John Rodda and Whittier police officer John Casselman. The city attorney, Rebecca Windt Pearson, said Monday that the city was still reviewing the lawsuit and didn't yet have a formal response.

Anchorage attorney Anne Helzer and Nathan Kellum, a lawyer for a Tennessee-based legal nonprofit called the Center For Religious Expression, are representing Grisham and Watson. Grisham runs a group called Last Frontier Evangelism and Repent Alaska, and has made headlines elsewhere, including for trying to start a boycott after an openly gay mayor was elected in Houston, Texas.

In the lawsuit, Grisham and Watson say they decided to attend the Forest Fair on July 8, hoping to find "a significant audience for their Christian message." After shuttling in, Grisham and Watson approached the fair and noticed signs outlining the rules against religious orders, the lawsuit says.

Neither believed the phrase applied to them, because they did not consider themselves part of a religious order, according to the lawsuit.

The city and Grisham and Watson have different versions of how events unfolded from there.

Grisham said he separated from Watson and spent about 20 minutes walking through the fair, "peacefully" handing out leaflets and talking to people, the lawsuit states. He was approached by security guards in red shirts who ordered him to stop handing out religious information, the lawsuit states. Grisham said he told the guards that it was a public park and a public event and he had a constitutional right to be there.

The guards took his arms and frog-marched him to a security tent and held him there until police arrived, according to the lawsuit.

When Whittier police officer John Casselman showed up, he told Grisham to leave the park. Casselman said Grisham was "distributing religious literature against the wishes of the event organizer," the lawsuit states.

Elsewhere in the park, Watson was also escorted out by a security guard, according to the lawsuit. She said she cited federal rules about religious expression, but organizers rebuffed her, the lawsuit says.

She and Grisham moved to the sidewalk beyond the park boundary but found it "vastly inferior" for distributing their message, the lawsuit states.

Sherwood's letter to Grisham's lawyer tells a different story. The letter describes Grisham and an unnamed woman speaking loudly and trying to pass out brochures to fair attendees.

Grisham was "even aggressively approaching Fair goers in an attempt to speak to them," Sherwood wrote in the letter. Fair staff told them to leave, and when they refused, the staff contacted police, Sherwood wrote.

Sherwood wrote that Grisham and Watson continued to preach and pass out religious literature at a new location on a public sidewalk for several hours near the intersection where Casselman, the police officer, directed them. As a result, the two weren't stopped from their evangelizing activities, according to Sherwood.

Sherwood said Grisham had many other options for spreading his message, such as coming to the park when it wasn't being used for a permitted event. He also pointed to the wedding example.

"If, as you seem to argue, anyone can use the park for any purpose, at any time, even when a permitted event is present, then there is nothing to prevent someone from coming in amidst the wedding and loudly speaking a point of view and attempting to hand out literature," Sherwood wrote.

Grisham and Watson's lawsuit says the permit contract for the fair requires it to remain open to the public. Neither Grisham nor Watson forced literature on fair-goers or approached people in an aggressive manner, the lawsuit contends.