Julian Fellowes doesn’t mask the true identity of Donna Murphy’s character in The Gilded Age: Mrs. Astor was, indeed, a real person and the queen bee of New York society. Although other women had the same family name, there was only one who was considered the Mrs. Astor: Caroline Schermerhorn. Frank Crowninshield, a Vogue society writer who knew Mrs. Astor, described her power as “absolute” and “long continued” in a 1941 issue.

Coming from an old Knickerbocker family—the descendants of the wealthy Dutch class that settled New York—Caroline Schermerhorn married William Backhouse Astor, whose grandfather had amassed a fortune through fur trading and real estate. Her husband’s extreme wealth, combined with her social pedigree, allowed her to reach and remain at the top of the upper echelon.

And Mrs. Astor was set in her ways: “Her taste was always for old families, old ways, old servants, old operas, old lace, and old friends. She tried always to keep society in bounds, to see that it was decorous, elegant, and select,” wrote Crowninshield. “Certainly, no subsequent period, or group of fashionable people, in American life has been so decorous or so admirably kept in hand.” Together with Ward McAllister, she developed Mrs. Astor’s 400—the 400 socially acceptable New York families. (Four hundred, by the way, was the number of people who could fit in Mrs. Astor’s ballroom.) In 1892, the list was even published by The New York Times.

Yet as American wealth exploded in the late 1880s and 1890s, her power began to wane. She eventually accepted the presence of the Vanderbilt family and several other industrialist families—whom she had previously excluded—because their wealth was greater than hers. Eventually, she could no longer be the sole social gatekeeper: “When the century turned, the task became too onerous for her. A thousand newcomers were at the gates; her strength waned, rituals became relaxed; other queens were in the making,” wrote Crowninshield.

Alva Vanderbilt

Left: Getty Images; right: HBO