It was a watershed moment in British-American statesmanship.

A sitting British ruler—King George VI–visited an American president—Franklin Delano Roosevelt—on his home turf. The four-day excursion “featured all the staples of a royal visit: a sight-seeing tour of Washington, a formal State Dinner and a big bash at the British Embassy,” writes Jason English for Mental Floss. But there were more casual moments, too: like the picnic where the king had his first-ever hot dog.

George visited with Queen Elizabeth (better remembered today as “the Queen Mum”). On June 11, 1939, the royal pair joined FDR and others at his Hyde Park “cottage” (read: mansion) in New York for a less-formal picnic. The menu, as quoted by English, included “Hot Dogs (if weather permits).” Thankfully, the weather held.

“KING TRIES HOT DOG AND ASKS FOR MORE” was the headline The New York Times ran with the next day. According to reporter Felix Belair Jr., the King enjoyed his two hot dogs with beer, and away from prying eyes: although members of the party had cameras, “no reporters were present and regular photographers were barred.”

“In the formal language of diplomacy, perhaps, the presentation of a hot dog may say: ‘On behalf of the United States of America, may we offer you this tubular delight of meat, meat byproducts, curing agents and spices?’” writes Dan Barry for the Times. “But what it really says is: ‘How ya doin’? Wanna beer?’”

The sitting president likely expressed himself in slightly less colloquial terms. But the picnic was an opportunity to meet Americans with their hair down—or at least more casually styled. “It would be difficult to imagine a more representative cross-section of American democracy than was to be found among the relatives, friends and neighbors of the Roosevelts who received invitations to the picnic,” Belair wrote. The royals also met the Roosevelts’ staff, including one employee who brought nine of his ten children.

But the British pair needed some etiquette advice to navigate this new social setting, Barry writes. While the hot dogs were served on a silver tray, he writes, “the royal guests nevertheless joined everyone else in eating off paper plates.” According to one story, the queen supposedly asked Roosevelt how one ate a hotdog. “Very simple. Push it into your mouth and keep pushing it until it is all gone,” he is said to have told her. She elected to use a knife and fork instead of taking this folksy advice.

FDR even drove the party up to the cottage in “his own specially equipped automobile,” Belair reported, and after lunch the king and the president went swimming together for the second time. Previously, they’d shared the pool that the paralyzed Roosevelt had installed at the White House to help him get exercise.

But the visit wasn’t all charming picnics. According to The Canadian Encyclopedia, the trip was a diversion from the royals' Canadian tour undertaken in the shadow of World War II, which broke out in Europe just months later. King George’s notes from the visit reveal that Canada’s Prime Minister Mackenzie King briefly joined the leaders at Hyde Park to talk strategy.

In his 1938 invitation to the king, Roosevelt also suggested he visit the 1939 World's Fair in New York, and wrote that Hyde Park might be a good place for a visit, as it's "on the direct route between New York City and Canada." "It occurs to me that a Canadian trip would be crowded with formalities and that you both might like three or four days of very simple country life at Hyde Park," he wrote. With war on the way, though, even that diversion had to include some business.