Sir Allan Napier MacNab was Canada's pre-Confederation prime minister for three years and the duchess' great-great-great grandfather.

Camilla and Prince Charles will tour MacNab's home, Dundurn Castle, in Hamilton as part of their 11-day visit to Canada.

"We're always very welcoming, obviously, to descendants of Sir Allan's, but to be able to have a visitor of that stature in society come out is just incredible," said Tom Minnes, the curatorial assistant at Dundurn.

"It will be a chance for us really to introduce the Duchess of Cornwall to her Canadian ancestors and her Canadian ancestral home through portraits and family objects."

MacNab is referred to as either the premier or prime minister of Upper Canada from 1854-56 for leading the provinces and is thought of as an early nation builder, Minnes said.

"He dies in 1862, five years before Confederation, but in a sense he was beginning to sow the seeds of Confederation through his interest in railways, tying Canada together," he said.

MacNab also helped suppress the Upper Canada Rebellion of 1837, for which he knighted in 1838 by Queen Victoria.

Camilla is descended from MacNab through his daughter Sophia - pronounced Soph-eye-ah. She married into the upper levels of English society, to William Keppel, who became the 7th Earl of Albemarle. Continued....