Peter Joseph Bis. (Photo by Marc Alain Bohn)

Peter Bis may have been the most rootless savant on Capitol Hill. He lived most of the past decade on the streets near Union Station without an address, a phone, a job or even a reliable connection to reality (unless the former law student with the uncanny memory really was Princess Diana’s former lover and a onetime aerospace magnate).

But in the week since Bis died of an apparent heart attack near his favorite corner at Second Street and Massachusetts Avenue NE, his many acquaintances — from think-tank economists to Hill waiters — have been marveling at just how deep a homeless man’s roots can sink into a busy neighborhood.

“Oh, no,” Senate Foreign Relations Committee staffer Emily Mendrala said with a small gasp, stopping short in front of the shrine that’s grown around the base of the oak tree where Bis held curbside court for years. She hadn’t heard. “This is so sad. He spoke to everybody. He made you smile.”

Bis, 61, will be cremated and his ashes sent to a younger brother in Kalamazoo, Mich. A lawyer, appointed by the courts last year as guardian of the mentally ill Bis, is making the arrangements. One of the neighborhood churches, St. Joseph’s, is planning to organize a memorial in coming weeks. A crowd is expected.

“He knew everybody here, everybody,” said Gary Bockweg, who passed Bis four times a day on his walks between his home and his job at the Federal Judiciary Center a few blocks away. “If you stood here talking to him for 10 minutes, he’d greet 50 people by their first name. And then he’d ask about their spouses. ‘Hey Joe, how’s Judy? You’ve got a baby coming in two weeks, right?’ The guy had an incredible memory.”

Even before any formal memorials, an ongoing one is unfolding on Bis’s old corner, where friends are dropping off flowers or packs of the Camels he loved and remembering him as a friendly and fascinating enigma, clearly intelligent, seemingly schizophrenic and relentlessly cheerful.

His catchphrases live on in the memories of Hill dwellers: “Four days until the weekend,” he’d rasp in his distinctive voice to passersby. “It’s 10 a.m., tea time in London, cocktails in Singapore.” One of the most common, and inexplicable, is tacked up in printed form to the tree: “No skinny dipping!”

His audience — his family, really — was the never-ending parade of humanity pouring in and out of the train station, the Congress, the Heritage Foundation offices down the block. Also the waiters at Armand’s Pizzeria, where he used to store his many piles of clutter each night, and the workers at the Exxon where he not only used the bathrooms but kept them clean.

“We looked out for him; he was a peaceful guy,” said Joseph Rohayem, co-owner of the gas station. Bis would use his computer sometimes and, on the coldest nights only, he would sleep in the garage.

Otherwise, he made his bed outdoors. “I grew up in Michigan; we do winter camping,” he told WAMU (88.5 FM) radio several years ago. “I’m good to 30 below zero. Seriously. I don’t think Paris Hilton is going to come by and pick me up in a limousine.”

But if Bis was usually upbeat, he was also clearly ill. His conversation combined a deep understanding of current events, which he gleaned by voraciously reading discarded newspapers, and impossible flights of fantasy and conspiracy. In his fractured telling, Bis was an alien from another galaxy, an enemy of the state, the victim of unending persecution.

“He often said that Bis stood for British Intelligence Services,” said Bockweg.

The illness appeared in Bis’s adult years, his brother James Bis, 51, said by phone from Portage, Mich. He frequently wore a lead-lined baseball cap wired with red lights. His schizophrenia was eventually diagnosed, and his family petitioned to have him committed for treatment.

Bis had grown up in Kalamazoo, the son of two teachers, near Western Michigan University, where he graduated with a degree in history in 1974. He did a year of law school in Lansing, and then worked as a hotel night clerk and started a car-painting company.

After a few months of in-patient treatment for his illness, Bis took to wandering the country.

“He never hitchhiked, but people would give him rides,” James Bis said. “He crossed the country two or three times.”

Peter was a “harmless kind of schizophrenic,” his brother said, who rarely lost his temper but also avoided getting help for his condition.

“He never drank alcohol or took drugs,” James Bis said. “He just smoked cigarettes and drank coffee and thought he was from another planet.”

After spending some time living near the United Nations building in New York, Bis migrated to another power center, Capitol Hill in Washington. His brother said the neighborhood reminded him of the bustling international feel of their youth near the university. Bis called home often, borrowing cellphones from his friends on the street.

“I got some very interesting names on my caller ID,” James Bis said. “I’d say, ‘Why are Capitol Police calling me, or some congressional office. ‘Oh, it’s Pete . . . ’ ”

Peter Bis became well-known as a homeless guy who never asked for money, although he gratefully accepted bagels, leftovers and free coffee from hundreds of sidewalk benefactors.

When strangers approached, he gave them business cards listing the address of a blog titled “Peter Bis: Vatican, Finances, Mafia, Kalamazoo,” where he regularly laid down his extremely wide-ranging thoughts with the help of acquaintances.

“Evil spirits thought to include Laura Bush and Catherine Zeta-Jones wiped out civilizations on Mars and Venus,” according to one entry. “Hillary Clinton’s Senate seat is owned by the Mafia,” starts another.

Washington lawyer Marc Alain Bohn encountered Bis regularly when he was a Senate staffer in 2006. One day, Bohn was carrying an international law book when Bis yelled out that he’d been involved in an arbitration proceeding before the United Nations.

“He would sidetrack into these stories of CIA adventures he may have been involved in,” Bohn said, “but through all of that, I felt I got grains and nuggets of truth here and there.”

Bis once told Bohn that he’d turned down teaching positions, because the $48,000 salary was simply “not enough to live on in this area.”

At one point, Bockweg helped Bis move into a nearby apartment, which was provided by social services agencies to get him off the streets. But he filled it with so much clutter that he was evicted, Bockweg said.

Bis ended up back at the tree by the Exxon station. It was the place he considered home.

Jennifer Jenkins contributed to this report.