The family of one of Tenby's grand old hoteliers will be under the spotlight at the Radio Wales Look Up Your Genes open day which comes to the De Valence Pavilion next Saturday (February 8).

The story of Mario Thierry, who was the owner of the Imperial Hotel during the first part of the 20th century, was picked out by genealogist Cat Whiteaway as she looked for local subjects to research for the family history event and the series of radio programmes which follow it.

"I wanted to give people an example of what it was like to trace an ancestor or relative who came from abroad. The museum at Tenby had sent us some wonderful pictures of some of the town's old characters, and when I saw the one of Mario, I knew I wanted to find out more. He looks so sophisticated and urbane in this snap that I wanted to discover what his background was," she explained.

Cat discovered that the future owner of Tenby's Imperial Hotel had a cosmopolitan upbringing. He was born in Milan in 1882, but then lived in France. By the 1900s he had moved to London with his father Eugene and mother Leonilde, and in 1908 had made the first moves to become a naturalised British citizen.

Mario died in 1972, aged 90, but Cat was able to discover something about the high days of hotel life from one of Mario's old friends, estate agent Charles Birt, another former owner of the Imperial Hotel.

"When you're researching someone's past and tracing their name and family through old documents, you begin to feel as if you know them," said Cat. "I was delighted to find Mr Birt really had known Mario in his later days, and I was even more pleased that his character and ideas seemed to tie in with how I'd imagined him."

According to Mr Birt, the Imperial Hotel came into being when Mario's father came to Tenby and saw four houses on the clifftop where the hotel now stands.

The area reminded him of the French resort of Biarritz, and he immediately saw the site's holiday potential. When Mario owned the hotel – then known as Thierry's Imperial Hotel -he was determined that sophisticated continental standards were followed.

Mr Birt remembers that Mario would insist on all the guests having to dress for dinner, while the waiters all wore black ties and the porter was on call 24 hours a day.

He also remembers Mario starting the tradition of keeping guest books to record all the people who visited the hotel - including Winston Churchill, Anthony Eden and the then Princess Royal. The books listed the visitors' favourite foods, wines and the amount of tips they handed out!

Mario sold the hotel to biscuit millionaire Garfield Weston in the 1920s, while Mr Birt took on the ownership for 30 years from the 1960s.

Cat's looking forward to meeting Mr Birt when the roadshow visits Tenby, and to showing him details of Mario's family tree.

Although there are none of Mario's descendants now living in the town, she's hoping that two of his grandchildren will travel to Tenby from the south-east of England to find out more about their grandfather, and about the town's Imperial past.

The Look Up Your Genes roadshow at the De Valence Pavilion in Tenby next Saturday is being opened by BBC Wales personality Ray Gravell, and the doors will be open between 10 am and 4 pm.

There'll be plenty to interest anyone who wants to start looking into their own family tree, as Cat will be giving talks about how to start in genealogy and how to use the web to further your research. There'll be a cyber cafe with help on hand for those who want to have a go at the recommended websites, and plenty of expert advice from organisations like the Dyfed Family History Society and The Pembrokeshire Record Office.

And - to give a sense of living history - there'll be a replica wartime kitchen, complete with two historical enactors, "Mrs and Mrs Jones", who are dressed in period costume and will be firmly stuck in the days of February 1943. Meanwhile Pembrokeshire WI members will be providing a taste of wartime Wales - delights like carrot cookies, carrot jam, war cake and potato scones.

If you can't get to the roadshow, the Look Up Your Genes radio programmes presented by Charlotte Evans with help and advice from Cat are on Sundays at 12 noon and Thursdays at 6 pm on BBC Radio Wales starting on Sunday February 9.