Rosemary Totton had been searching for information about her great-great-great-great-grandfather Israel Samuel since 2003.
And on discovering that 250 years ago, he was the first Jew to settle in Brighton, Mrs Totton, husband Alan and son Joshua made the 11,000-mile journey from their New Zealand home to witness a blue plaque ceremony organised as part of the anniversary celebrations.
The 59-year-old said that she had found out about the ceremony "by chance" during an online search. "I had no idea anyone else would be interested in him. It's exciting to be here. Seeing that name on a blue plaque was a beautiful feeling. I'm still pinching myself. We're all exhausted with jet lag and it's overwhelming."
The blue plaque was unveiled at 22 East Street, now a Crabtree & Evelyn store, the location of Mr Samuel's silversmith's business (he also sold toys and clothes).
Once in Brighton, the Tottons began to appreciate their ancestor's role in local Jewish history. "We can see the city where he lived, the alleyways and beautiful buildings and get a feeling for what it looked like. I saw his signature at the bottom of a document which allowed the community here to obtain a room for the synagogue. It's incredible to see my ancestor's signature - and the closest I am going to get to him."
The ceremony had demonstrated that "you don't have to be outstanding or brilliant to be remembered. You can just be a pious family man."
Their visit also established another family connection. "We met a cousin we had never seen before," Mrs Totton said. The local community had made them feel at home. "It's been a special day."
Joshua, 26, added: "For so many years we've heard the family stories about this Jewish ancestor. But it's all been bits and pieces and very abstract.
"Meeting relatives we've never seen before has made it all very real. We thought it would be a small unveiling and a cup of tea. But so many people came and spoke."
Civic and communal leaders were among the 250 people at the plaque unveiling, a record for such an event in Brighton. A local big band played both God Save The Queen and Hava Nagila.
The 250th anniversary programme is being directed by Ivor Caplin, the former local Labour MP.
He said the blue plaque event was "amazing for the city and the Jewish community. It shows the standing we have in Brighton and Hove.
"It's been a moving day and one which no one here will ever forget."
Special Shabbat services are being held in local shuls to mark the 250th, the next being at the Progressive synagogue this weekend and at the Orthodox New Church Road on July 30.
The historic Middle Street Synagogue - dating back to 1875 and long closed as a place of worship - will open its doors for a heritage weekend in September and November's local Ajex remembrance service.