And a second theft was reported on June 3 after staff noticed a bronze model of a goat had been swiped from another room open to the public.
Karen Seaman, press officer for Holker Hall, home to Lord and Lady Cavendish, says such incidents are “rare”, but regrets it has prompted tighter surveillance with more cameras and further training for staff.
She said: “We are quite lucky here in that we rarely have anything like this happen, but obviously now this has happened we have upgraded a lot of our security operation and are being extra vigilant now.
“At Holker Hall there are no barriers so there is nothing to stop the public looking round the room. Lord and Lady Cavendish would hate to have barriers, but it is not something we are considering at the moment.”
The ring holders are mounted on square malachite plinths. One was 10 inches tall and surmounted by an eagle, the other 11 inches tall and surmounted by a swan and had some damage to the plinth.
The goat model, found to be missing on June 3, is eight inches wide and also dates from the 19th century.
Ms Seaman said: “We are quite convinced the second item was there after the weekend because we had a sweep round to check if anything else was missing. The cleaner was convinced that she had seen it the day before.
“It’s a real shame. They are lovely things. They are property of the family and they are really disappointed and quite upset about it.”
Police are appealing for any potential witnesses or anyone with information to contact them on 0845 3300 247.