For “Downton Abbey” fans, Highclere Castle remains a lasting reminder of the popular British television drama and the Crawley family’s struggle to adapt to a rapidly changing world of telephones, gramophones and women’s rights.

But for Canadians, the Victorian country house may have been the setting of a historic meeting that altered the course of Canada’s history.

Lady Carnarvon, the modern-day lady of the house, has done extensive research on the castle’s history. She says that records show that Canada’s first prime minister, Sir John A. Macdonald, met with a group of men at the castle in December 1866 -- seven months before Canada became a country -- to discuss, debate and draft much of the Canadian constitution.

Among the group was Lord Carnarvon, the minister in charge of British colonies.

“Lord Carnarvon didn’t wish to see Canada submerged into the U.S.,” Lady Carnarvon explained in an interview with CTV News in the castle’s library. “This is where it happened.”

The discovery has a direct link to “Downton Abbey” -- specifically episode two of season one, when Violet Crawley, the acerbic dowager played by Maggie Smith, famously remarks during dinner banter: “What is a weekend?”

Lady Carnarvon says the line made her curious to research who visited the castle on so-called “weekends.”

“When I got the visitor’s book to research the weekend, I picked one with lots of lovely people here. And then suddenly you get a man’s signature here: John Macdonald,” she said, pointing to the name in the guest book.

Her research into Macdonald’s visit dug up plenty of historic tidbits. Macdonald spent many nights at the castle and ate in the dining room. In fact, according to Lady Carnarvon, Macdonald enjoyed socializing a bit too much, and Lord Carnarvon had to order his butler to cut back on refilling the future prime minister’s drinks.

Fictional and historical plotlines roam the halls of Highclere Castle, and Lady Carnarvon says she’s thrilled that her home can be the backdrop for both.

“For me, the show is amazing. It’s given us a marketing platform. But something like this matters enormously to me. To think that all these extraordinary men were here, pioneers, so brave, trying to create a constitution, trying to create a new country.”

With a report from CTV’s Daniele Hamamdjian at Highclere Castle