Margaret Helen Greville and Grace Kelly both came from families with humble origins that earned wealth rather than inherited it. However Margaret Helen was considerably edgier than Princess Grace. Margaret dressed to be noticed. Perhaps she was not as gorgeous as Princess Grace or perhaps a few Oscars and a few years on theater marquees world-wide may have taken some of the edge off of Lady Margaret.
There is an excellent biographical article about her, from which the following was distilled, in The Esoteric Curiousa here. She was the illegitimate daughter of beer baron William McEwan and she was quouted as saying "I’d rather be a beeress than an heiress!” In 1891, she married Ronald Henry Fulke Greville, “Ronnie," eldest son and child of the four children born to Algernon Fulke Greville, 2nd Baron Greville and his wife Lady Beatrice Sybil Violet Graham. She and Ronnie had no children; if they had, Maggie claimed she would have given up much of her social life to be with them. Ronald died on April 5, 1908, predeceasing his own father and never ascending to the peerage. Following the premature death of her husband, Maggie divided her time between travelling abroad, and holding lavish dinner parties at both Polesden Lacey, a grand country house they had restored, and her London home. She became the "prima donna" of Edwardian society hostesses over the next 30 years, as famous for her exquisite French cuisine as for her distinguished guests.
Over the years, Mrs. Greville had accumulated and owned a fantastic collection of jewels. It was her practice to wear jewels to impress, preferring size to quality and provenance. As such, she tended to be disparaging about the jewels of other society ladies. Once when a rich American lady lost the principal diamond of her necklace, and the guests, on all fours, scrambled for it on the floor, Mrs. Greville was heard addressing a footman, "Perhaps this might be of assistance? She proffered a magnifying glass." When asked what she thought about Lady Granard’s fabulous pearls, she was dismissive, "I thought it better not to look." James Lees-Milne, one of those that helped spearhead the bequest of Polesden Lacey to the National Trust, wrote in 1942, "Mrs. Greville had left Marie Antoinette’s necklace to the Queen." and others have written of Empress Josephine’s emeralds and diamonds, and a diamond ring that had belonged to Catherine the Great.
She bequeathed to Queen Elizabeth, the Queen Mother "with my loving thoughts all my jewels and jewelry except such as in hereby or any codicil hereto specifically bequeathed’ and a legacy of £20,000 to Princess Margaret, suitable sum." Mrs. Greville’s bequest to the Queen Elizabeth, the Queen Mother, included the openwork diamond tiara designed by Lucien Hirtz, which Maggie had ordered from Boucheron in January 1921. There was a magnificent five strand diamond necklace, a set of diamond earrings, and a set of heavy chandelier earrings, just to list a few.