After six seasons of non-stop suffering, Lady Edith finally found happiness in the last chapter of Downton Abbey’s period saga, which aired Sunday night in the U.S. To celebrate, we dialed the drama’s producers Gareth Neame and Liz Trubridge to find out how they secretly strategized the middle Crawley sister’s much-deserved moment in the sun. Fair warning, though: if you have not yet watched the series finale, which aired on Christmas in the U.K., avert your eyes from the spoilers below.

Speaking to Neame and Trubridge separately by phone last week, we asked when they knew that Edith would be getting the happy ending—complete with reconciliation and wedding to Bertie—that she deserves.

“We started thinking about how it would end for each character as early as the fifth season,” explained Neame. “Because these characters are so beloved, it was very enjoyable to work out exactly where we wanted them all to end. Particularly the key stories; like, for Edith: How she is going to end up triumphing over the whole rest of her family?”

Series creator Julian Fellowes, who wrote all of the episodes, cleverly kept audiences in the dark about Edith’s reversal of fortune by introducing her love interest Bertie as a man of modest means and expectations, who only ended up leapfrogging the peerage system upon surprisingly inheriting the title of Marquess of Hexham in the show’s sixth season.

Of the clever plotting, Neame said, “I think [Fellowes] very deftly thought through that she would, in the usual Edith way, meet a nice guy who is not very inspiring, not very exciting—a very low-key kind of individual—who by complete fluke ends up inheriting this big title and this huge castle and all this money. The moment Julian said, ‘I think that’s what should happen,’ I just thought that was the perfect story. We certainly had increasingly felt that Edith had been so unlucky over all these years that it would make for a wonderful resolution if finally things would start to go right for her.”

The show’s creatives were careful not to go too overboard with Edith’s bliss, though—and relished orchestrating one last bruising: when Mary cruelly tells Bertie the truth about Marigold in the show’s second-to-last episode.

“Of course, it can’t be too plain-sailing in a drama series,” said Trubridge, “so the penultimate episode, where the sisters really showed their loathing of one another, was a very good springboard for Edith.” Although Downton Abbey’s decision makers weren't quite sure Mary was capable of being that wicked.

“We debated whether Mary spilling the beans about Marigold was going too far, and whether audiences would stomach that,” Neame conceded. “We wondered whether it was just too evil to have Mary be the one who finally tells the truth. And for a few seconds, we thought, ‘Oh, that’s just the nastiest, most loathsome thing Mary has ever done in all these years.’”

Laughing, Neame added, “But we really enjoyed taking Mary to such a dark, dangerous place. We really only talked about it for a few minutes, and then we said, ‘Oh, we’ve got to do it. It’s so strong.’”

In the original version of that episode, though, Edith actually held her tongue and did not (rightly!) lash out at her sister afterwards in the most satisfying altercation of the series.

“In the first draft, Julian hadn’t written the fight that follows,” Neame said. “And I said, ‘We’ve got to now have the biggest fight they have ever had.’ These feelings have been simmering under the surface for so long. And he said, ‘Yep! You’re right.’ Shortly later he sent [the new draft] back to me, and it was such a good scene. So enjoyable. It’s the only time we've really ever heard them swear like that—Edith calling Mary a bitch—and so out of character.”

Speaking of Edith’s unexpected transformation, from mousy Season 1 sister to the woman telling off Lady Mary, Neame confessed that even the show’s masterminds didn’t know Edith was capable of such strength. “Edith has just gone on this journey that none of us had quite figured out at the beginning. But it sort of evolved. At every turn her life started moving in the alternative direction from what she had planned. Eventually she works out that she’s going to have this career.”

Some audience members might have seen Edith as a trailblazing ancestor for Sex and the City’s protagonist Carrie, and in a similar conundrum. She’s an established career woman with a fabulous editorial job in the city and, as much as some viewers want her to find romantic happiness, others might have wondered whether the character could have been fulfilled without a man—despite how rare it would have seemed to be a satisfied “spinster” during that time period.

“I think our view is that could have been fine,” Neame said, when asked whether Edith could have had a happy ending sans man. “But maybe in the context of the show, which is overwhelmingly a positive show about traditional happiness and people trying to get the best for their lives, it felt right that she should finally have some personal happiness as well as being a successful business woman.”

Though Trubridge points out, “It seemed important that she actually found her independence first, before marrying, because then it felt like she would never lose that.”

And of course, marrying Edith off wasn’t just meant to satisfy the traditionalists in all of us, but to give audiences the delicious plot twist of Edith besting her competitive sister in the marrying game.

“The thing that really appealed to us was that after six years of Mary trying to marry a Duke, it was Edith in the end who sort of crept up like the tortoise behind the hare,” said Trubridge. “And actually bagged a man who accords her a higher status than anybody else. Edith has probably developed most of the Crawleys over the six seasons, from that mousy, in-the-shadows sister in Season 1 who was not remotely threatening.”

The way that Edith handles the final obstacle between herself and happiness—telling Bertie’s morality-obsessed mother about Marigold—is proof positive of Edith’s full transformation. Standing up and asserting herself, and her moral failings, is something of which Season 1 Edith would never have been capable.

Even though Edith does get the happiest ending of Downton Abbey’s characters, Fellowes still had his fun toying with the audience’s low Edith-related expectations. In an early scene in the finale, Lord Grantham rushes into the master bedroom, telling Cora that she is never going to believe the latest news about Edith. As conditioned for Edith-related tragedy as the rest of us, Cora deadpans, “She’s pregnant again? She’s been arrested for treason?”

Lord Grantham alerts her that Edith’s wedding to Bertie is back on. And when Cora has the nerve to cite a scheduling conflict, Lord Grantham reprimands her on the audience’s behalf, scream-lecturing, “This is your second child who has hardly known a day’s happiness in the last 10 years!”

Thank God, Edith finally gets her wedding. Asked how the show’s producers wanted to consciously differentiate Edith’s nuptials from Mary’s weddings, Trubridge explained, “Because Edith is older and she has a daughter, the wedding is more low-key than Mary’s first was but it is still a beautiful wedding. To have that moment when she comes down the stairs, which echoes Mary coming down the stairs from eight years earlier—was very special.

“We’ve done weddings before on the show, but we haven’t done much of the reception,” said Trubridge. “So we wanted to make it more that we saw Edith happy and married, because we’d had so many moments at the altar. We wanted a takeaway. We wanted to see her in her wedding gown.

“Poor love really had a lifetime share of bad luck,” concluded Trubridge. “It was nice to see her bask in her time. God knows she’s earned it!”