Looking back, their love story was both royal and implausible.

She was the daughter of King George VI. He was the nephew of a deposed king of Greece.

Her family owned majestic castles. His family was living in exile.

Her father helped rally Britain over the Germans in World War II. His sisters had connections to the Nazi party.

Also, they were cousins — distant, but still cousins.

But when they strolled out of Westminster Abbey in 1947 as husband and wife, Princess Elizabeth II and Prince Philip, who died Friday at 99, embarked on a love story for the ages.

Married for nearly 74 years, their royal matrimony weathered her unexpectedly early ascension to queen, after which his Royal Navy career took a back seat to her duties as head of state — her weekly audiences with prime ministers, the gilded life of the Sovereign.

Though the popular Netflix show “The Crown,” portrayed Prince Philip as unhappy in those early days, the truth is that “Prince Philip took on the unlikely role of champion to his wife and became both mother and father to their children, allowing the queen to deal with the requirements of her position,” according to royal biographer Ingrid Seward’s 2018 book on their marriage.

“Even after seven decades,” Seward wrote, “the Queen’s face lights up when Philip enters a room.”

The first time they remember laying eyes on each other was in 1939.

She was 13, prim and proper. He was 18 and unrefined — a dashing cadet at Britannia Royal Naval College. Europe was months away from being consumed by World War II.

Margaret Rhodes, the queen’s cousin, wrote in her 2011 autobiography, “The Final Courtesy,” that “Elizabeth was truly in love from the very beginning.”

During the war, the two exchanged letters. Philip served in the Royal Navy while she was shuffled from palace to palace as Britain was being bombed. She eventually was settled with her younger sister, Margaret, at Windsor Castle.

Marion Crawford, who served as their governess, wrote in her memoir, “The Little Princesses,” that Elizabeth was smitten with Philip’s arresting blue eyes and Viking good looks.

But they waited until after the war to get engaged. When the crowds cheered their wedding at Westminster Abbey in 1947, neither of them expected she would be crowned queen anytime soon. Her father, King George VI, was in his early 50s. Philip, named Duke of Edinburgh, intended to continue his career in the navy. But the king died five years into their marriage, and Elizabeth became queen at the age of 25.

Philip was forced to quit his naval career. In 1992, he told an interviewer, “I’d much rather have stayed in the navy, frankly.” He later called his resignation “naturally disappointing.” By many accounts, there was real tension in the marriage, and “The Crown” strongly hints that Philip was a serial cheater.

But he and Elizabeth endured, traveling the world together and producing four children, eight grandchildren and 10 great-grandchildren. According to Tatler, which chronicles the lives of the British royals, he teased her in private, calling her “Lilibet" and “Sausage.” Or sometimes just “Darling.”

Early in their marriage, Philip often took on the role of homemaker while his wife attended official events, according to Philip Eade’s book, “Prince Philip: The Turbulent Early Life of the Man Who Married Queen Elizabeth II." He hung pictures and moved chairs at one of the flats they shared. He loved gadgets, once picking up an electric mixer.

He even bought Elizabeth a gift that scores of husbands through the years have gifted their wives — a washing machine.

“Philip was an avid homemaker,” Eade wrote.

Britain's Prince Philip, husband of Queen Elizabeth II, died at age 99 on April 9 at Windsor Castle. (Alexa Juliana Ard/The Washington Post)

But he was also a frustrated one. Philip did not like all the formality. He preferred carrying his own bag, making his own martinis and talking to people himself — not through memos or messengers. While he yearned to have his old military career back, royal observers have written, Philip eventually came to enjoy his role as Elizabeth’s sidekick.

If marriage is a constant give and take between husband and wife, so it was between the queen and her prince.

The queen’s job demanded she be a rigid traditionalist. But Philip was decidedly not a traditionalist in filling his royal duties.

He refused, Eade wrote, to have his speeches written by a committee of palace public relations officials. Instead, he wrote his own or simply spoke from the cuff, often leading to notable gaffes. Philip also still insisted on hanging out with his old pals at clubs, which led to constant rumors of infidelity.

But the unlikely marriage would survive Philip’s fierce independence.

One of the last public images of them together was on their 73rd anniversary last year.

They were sitting together. Elizabeth, in a pretty light purple dress. Philip in a suit. They were looking at handmade anniversary cards sent to them by their great-grandchildren. They were smiling — the queen and her prince, husband and wife, proud grandparents.

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