The mystery began, Graham Farrell said in a phone call from England, when he opened a box that contained his late father's most important possessions.

Inside was a sealed envelope. And on it, scrawled in his father's elegant hand, was written: "Very dear to me."

Farrell, the sole son among six siblings, came across the box as he settled the estate of his father, Albert Edward Farrell, in 2003. But only recently could he bear to open it.

In the envelope he found three pieces of paper: A tattered invitation to a 1946 wedding - in Philadelphia, of all places. A black-and-white photograph of a couple and their children, dated 1953. And an old employment card from Canadian Pacific Steamships.

All three bore one name in common: Kay Bonner, the woman to whose wedding Farrell was invited.

The younger Farrell, 64, doesn't know Bonner, why his father kept these mementos, or what connections they signify. He wrote to The Inquirer in hope that a news story might jog memories and offer answers.

"The whole thing intrigued me," Farrell said from his home in Liverpool, the birthplace of the Beatles.

Farrell, who serves as a justice of the peace for the City of Liverpool, was close to his father. And his father was proud that the son of a working-class family should be employed in the service of the queen. The elder Farrell worked as a Liverpool bus driver, a job he took after the end of World War II.

During the war he'd forged a tie to the United States, enjoying the banter and friendship of American soldiers he met while serving in the Merchant Navy.

"He was on the Queen Mary when they were bringing veterans back to the U.S.," Farrell said. "He loved America."

His father regularly went ashore in New York, and "I'm almost sure he mentioned he'd been to Philadelphia," Farrell said.

The senior Farrell lived alone after his wife died. And when he died at age 80, his son found his ditty box, a small wooden container where seafarers keep important papers.

When he finally looked inside, he found the sorts of papers that anyone might hold onto. His father kept the certificate from his 1930s wedding to his wife, Iris. He kept some war records, and his wife's birth certificate.

And the envelope.

Dual bells mark the wedding invitation of Katherine Frances Bonner and Francis C. Nuneviller on Aug. 24, 1946, at Holy Cross Church.

Tucked inside that was an employment card from the Duchess of Bedford, of Canadian Pacific Steamships. Farrell's name appears in pencil on the front. On the back is written, "Miss Kay Bonner, 244 Sydney St., Philadelphia, Pa.," and below, "Eleanor B. Currie, 253 Sydney St., Philly, Pa."

The 1953 photo shows a group of people standing by a car on a country road, waving to a couple and two children at a second car. On the back is, "Kay Bonner, Philly, USA," and a note apparently penned by her: "Frank, the girls and I, and Frank's pride and joy - his car."

Searches by The Inquirer produced no solution to this transatlantic puzzle, but did turn up some additional information:

Officials at Holy Cross Church confirm that Katherine Bonner and Francis Nuneviller were married there in 1946.

Katherine, of Quakertown, died in 2006 at 78, according to her obituary in the Allentown Morning Call. Her funeral was held at St. Agnes Catholic Church in Sellersville.

Her husband, Frank, is still alive - an 88-year-old retired truck mechanic in Quakertown. When he and his wife wed, the war had just ended. Nuneviller had served in the Navy Armed Guard, protecting Liberty and merchant ships.

In an interview, Nuneviller vividly remembered the war years, but said he could not recall anyone named Albert Farrell. If they met, it would have been one time, at the wedding. His wife had family in England, Nuneviller said, but all are gone now.

"Albert Farrell, no," he said. "The name's not familiar to me."

Carol McCool knows the people in the black-and-white photo. And that's her in the backseat, about age 5, with her sister - and her mother and father standing by the car door. The picture was likely taken in Ohio, at a family gathering.

How did the photo end up among the papers of a man in Liverpool? No idea, she said. "The name Farrell didn't ring any bells," McCool said.

Still, the younger Farrell hopes someone - perhaps a long-ago friend or distant relation - might shed light on papers, and memories, that were precious to his father.

"It was a long shot, but I had to do it," he said. "What was my dad's connection?"

Contact Jeff Gammage at 215-854-2415, jgammage@phillynews.com, or on Twitter @JeffGammage.