Investigators are working to determine the cause of a fast-moving fire that destroyed a historic, 21-room mansion in Newport, Rhode Island, the seaside city where Gilded Age mansions attract hundreds of thousands of tourists every year.

The Stonor Lodge, which has played host to luminaries including Jaqueline Kennedy, was not occupied at the time of Thursday's fire and was undergoing a major renovation. Jerry Kirby, owner of the construction company, told The Newport Daily News a carpenter noticed the fire late Thursday afternoon and called 911. No one was hurt.

The house was built between 1870 and 1880 and owned for generations by the family of socialite and philanthropist Noreen Stonor Drexel, who died in 2012. Her late husband, John Drexel III, was head of a powerful Philadelphia banking family. His great-great-grandfather, Anthony Drexel, was a business partner of financier J.P. Morgan and founded Drexel University.

After her death, the house was sold for $3.3 million in 2013 to a company based in New York.

Donald Christ, a family friend, had stayed in the home many times over the years and said that while it was 9,000 square feet, it felt "homey."

"I found it very lived in and very comfortable," he said.

Kennedy was close friends with the family and was known to spend time at the home, Christ said. Her family had a farm in Newport.

Christ called Stonor Drexel an incredibly important person in the city's history and said the fire marks "the end of an era."

___

This story has been corrected to show the fire was discovered late Thursday afternoon, not late Thursday.