As an historian of nineteenth and twentieth century Britain and Ireland, I resisted watching Downton Abbey for a long time. I’ve been immersed in the 1920s and the 1930s for over a decade, and I was afraid it would be like seeing all of my favorite books made into one terrible movie, every single week. I also didn’t want to be that cranky person in the corner pointing out anachronisms that don’t really matter to anyone. Finally, my friends lured me over one Sunday night with offers of whiskey cocktails and sticky toffee pudding. And I realized I’d been wrong. It doesn’t matter a bit that this is a confection of the early twentieth century—it’s gorgeous and fun, and even if it doesn’t always fully answer them, the show raises interesting questions about the social history of the period. Warning: there will be spoilers—I’m going to write as though you’ve either watched the episode or never plan to.

Widowhood was the emotional center of Sunday night’s double episode, as Lady Mary (Michelle Dockery) grappled with the aftermath of the untimely death of her husband, Matthew Crawley (Dan Stevens). The escapades of her younger sister, Lady Edith (Laura Carmichael), were meant to lighten the mood and show off some of the glamour of 1920s London. Lady Edith, of course, has been terribly unlucky in love, and is now involved with a married newspaper editor, Michael Gregson (Charles Edwards). Gregson, we learned last season, is not really the cad he appears to be: he can’t get a divorce because his wife is legally insane and thus unable to consent to divorce proceedings.

Between the two of them, Lady Mary and Lady Edith herald the huge shift that occurred in the twentieth century, from death to divorce as a major cause for the end of a marriage for younger people. As average life expectancies increased, it became less common for men and women to lose a spouse to death after only a short marriage rather than at the end of a long life together. Meanwhile, the slow liberalization of divorce laws saw an increasing number of marriages ended in the courts. According to one study, women born between 1900-4 had a life expectancy at birth of 56.8; of those who survived to 15, 83 percent would marry, and 64.3 percent of those marriages would end in widowhood. Divorce accounted for the end of just 3.9 percent. By contrast, women born in 1975 could expect to live to 75.9; 95 percent of those who survived to 15 would likely marry. Though widowhood was still forecast to be more common, ultimately, than divorce, the numbers were much closer: 49.4 percent of these marriages would end in widowhood, and 28.3 percent in divorce. For young women, of course, divorce would be much more common.

The relatively young, beautiful, tragic widow was a mainstay of Victorian British culture. After Prince Albert’s death from typhoid fever in 1861, Queen Victoria entered a state of permanent mourning, wearing black for the rest of her life (she died in 1901). Her extravagant devotion to Albert’s memory helped to nurture a larger culture of mourning, one that featured strict rules about color, clothing, and other accoutrements such as black-edged stationery and special jewelry. When Lady Mary appears at the luncheon table in purple rather than black, she is broadcasting her intention to enter the next stage of mourning and to leave the more intense, all-black phase behind. The massive loss of life caused by World War I fundamentally altered the landscape of mourning. Lady Mary remarks, somewhat caustically, that Gregson is not so bad: “He’s not bad-looking and he’s still alive which puts him two points ahead of most men of our generation.” Although, demographically, the gender balance in Britain was not drastically altered by World War I (because many young men who would otherwise have emigrated stayed home), her comment captures the reality of her social position: many young women of her age and class were premature widows or bereaved of their sweethearts because of the war.

At the same time, however, divorce was slowly becoming an option for an increasing number of English people. Under the 1857 Matrimonial Causes Act, ordinary men and women could try to get divorced (previously marriages could only be ended by church courts or special Acts of Parliament). While men had only to prove adultery, women were required to prove an additional factor such as cruelty, rape, or incest. In 1923, it became easier for women to petition solely on the basis of adultery. The Divorce Court operated on the logic of shaming spouses publicly for their bad behavior in order to encourage better marital conduct among those still married.

When this failed to keep the number of divorce petitions to a minimum, the Court began insisting that couples prove that they were not colluding, or agreeing to a convenient lie about adultery in order to end their marriage by choice. This led to a minor cottage industry that aimed to helped spouses provide the necessary proofs. Dorothy Sayers has a character refer to this farcical situation in Busman’s Honeymoon, the last of the Lord Peter Wimsey/Harriet Vane mysteries: “Which reminds me that my idiot great-nephew, Hughie, has bungled matters as usual. Having undertaken to do the thing like a gentleman, he sneaked off to Brighton with a hired nobody, and the Judge wouldn’t believe either the hotel bills or the chambermaid—knowing them all too well by sight.” In other words, the gallant but inept Hughie had hired witnesses to a faked adultery, but the judge recognized them from previous cases and refused to believe that any real adultery had happened.

In spite of the hassle and humiliation, the number of divorces grew steadily, from the low hundreds each year in the late nineteenth century to the mid-thousands in the interwar decades—2,588 in 1922, the year in which season four begins. If only Lady Edith and her wayward editor can hold out for another fifteen years, a solution is on the horizon for them (one that does not involve becoming a German citizen—or rat poison, Mr. Bates): in 1937, the divorce law was revised, and insanity became one of the grounds for divorce. It would not be until 1969, though, that couples could divorce without having to prove one or the other of them at fault. In 2013, the Office for National Statistics estimated that 42 percent of marriages in England and Wales end in divorce.

It’s tempting to wonder about the causal relationship between these two trends: did we need easier divorce because early death no longer provided a safety valve, in demographic if not individual terms, from dull or desperate marriages? What is certain, though, is that, in focusing on Lady Mary and treating Lady Edith as a sideshow, Downton Abbey is so far looking backward rather than forward; by 1922, the homewrecker and the divorcée were quickly replacing the widow in the pantheon of cultural stereotypes about women.