Tonight’s episode of Downton Abbey once again found the fictional Crawley family members rubbing elbows with real historical figures (previous familiar faces to interact with Lord and Lady Grantham include Dame Nellie Melba, as well as future king Edward, the Prince of Wales and his then-mistress, Freda Dudley Ward).

This time around, it was the eventual British prime minister Neville Chamberlain (portrayed by actor Rupert Frazer) who came to dine at the grand estate. But to use the words of Tom Branson, the meal “delivered more than [he] bargained for.” (SPOILER ALERT: In a deeply upsetting scene, Lord Grantham suffers a burst ulcer and proceeds to projectile-vomit blood all over the table and his guests).

While Chamberlain’s presence wasn’t vital to the episode’s plot (he was brought in by Maggie Smith's character, Violet, the Dowager Countess, as hired muscle in this season's ongoing hospital-takeover debate), his subsequent, pivotal role in British history makes this a good time to take a look at his background a little more closely.

Since Downton Abbey's final season takes place in 1925, the then-minister of health could appear as an innocuous dinner guest whose most interesting characteristic was that his brother-in-law was a notorious British prankster (he and Tom discuss this fact toward the end of the episode).

But just over a decade later, Chamberlain—having proved Downton cook Mrs. Patmore’s ever-so-prescient suggestion that he “may be prime minister one day”—would make several diplomatic decisions that would leave him in an unfavorable light as the United Kingdom edged closer into the Second World War.

In order to avoid giving the Downton Abbey characters too close of a connection to the man who would one day favor appeasement with Nazi chancellor Adolf Hitler—and be photographed shaking the murderous dictator's hand—the family link was made through Chamberlain’s real-life wife, Anne de Vere Cole. According to Violet, her late husband was Mrs. Chamberlain’s godfather.

At the time the Downton episode takes place, the idea of another world war wasn’t even a glimmer in Chamberlain’s eye, probably because the wounds from the Great War were still so fresh in everyone's minds. This is why one of the most substantial arguments that has been made for the appeasement decision is that Chamberlain was willing to do whatever was necessary to evade a repeat of the First World War.

Neville Chamberlain became prime minister in 1937, participating in what would become his most notorious act as leader of the British people one year later: the Munich Agreement. With German aggression looming, and war becoming even more of a foregone conclusion, Chamberlain met with Hitler, Italian dictator Benito Mussolini, and French Premier Édouard Daladier in September 1938. The resulting plan handed over the area of Czechoslovakia known as the Sudetenland to Germany.

In Chamberlain's opinion, this diplomatic decision would assure peace within Europe, and prevent any further atrocities of war. By this time, he may have had another decade to get over the events WWI, but even 20 years after the Armistice, a world war repeat wasn't high on Chamberlain's priority list.

According to historian David Dutton, the author of Reputations: Neville Chamberlain, in a 2009 piece for The Telegraph, the Prime Minister "had been deeply scarred by the memory of the First World War. Expert opinion predicted that any future war would be even worse: to the slaughter of the battlefield would be added unspeakable destruction from the air. Extrapolating from the Spanish Civil War, it was estimated that the first few weeks of a German air assault would bring half a million casualties: Britain was defenseless in the face of the bomber."

However, Chamberlain's decision of what he called "peace with honor" and "peace for our time" would ultimately be his downfall, even before Hitler broke the Munich Agreement by invading the rest of Czechoslovakia and then Poland in 1939. The man who would succeed Chamberlain as prime minister and lead the United Kingdom through the darkest years of World War II to eventual victory, Winston Churchill, castigated his predecessor's act of appeasement upon his return from Germany: "You were given the choice between war and dishonor," Churchill said. "You chose dishonor and you will have war."

Whatever promises of peace that had been made lay in a broken mess at Chamberlain’s feet by September 1939, forcing the prime minister to declare war on Germany following its invasion of Poland. He remained in office through the following year, but his popularity steadily declined over the next several months.

Historians like Dutton, in retrospect, do offer up arguments that Churchill may not have had any success in turning the tide of history if the roles had been reversed: "He overestimated his ability to reach a settlement with the dictators," wrote Dutton of Chamberlain in the same 2009 Telegraph article. "He probably clung too long to the hope of averting war. But it is doubtful if anyone else would have done much better, Churchill included."

Bereft of political support following an unsuccessful attempt to liberate Norway from German forces, Chamberlain resigned as prime minister in May 1940, with Churchill chosen as his successor. Chamberlain died of bowel cancer in November of that year.