It’s such a brief aside that Downton Abbey viewers might even not notice it — except that the subject matter is so out of character for the show. Yes, in the episode that aired Feb. 1 in the U.S., a nudist colony is the subject of conversation.

The Essex-based colony, known as the Moonella Group was — as we’ve come to expect from Downton — an actual thing. As The Telegraph explained in a 2006 look at the history of naked Britons, the Moonella Group was the first club to bring nudism (also known as naturism) over to the U.K. from the Continent, which it did in the years following World War I.

The modern British Naturism organization elaborates in its own history of the movement, Moonella was the code-name of the club member who owned the property where the camp was established. He or she invited some elite members of the New Gymnosophy Society to use the groups for their naturist needs, as long as they followed certain rules of decorum.

According to British Naturism, the original Moonella Group site only lasted a year or so. But, as TIME reported in July of 1929, nudism wasn’t going away any time soon — even if it faded from the public eye for a while:

Made in Germany, imported to France, is the cult of Nudism, a mulligan stew of vegetarianism, physical culture and pagan worship. The outstanding feature is that all devotees must live in a state of complete spectacular nudity. Much publicity has been given the Nudist colony on an island in the Seine near Paris. Lively have been their arguments, moral, economic, religious, with Prefect of Police Jean Chiappe over the matter of bathing trunks. Some weeks ago a young French reporter paid a secret visit to the Nudist colony. So depressing, so disillusioning was his published account of the flabby spectacle that the romantic French press and public lost interest in the entire business.

Read a 2003 story about modern nudists, here in the TIME Vault: Nude Family Values

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Write to Lily Rothman at lily.rothman@time.com.