Scholars say the first king of a united England was an Anglo-Saxon warrior named Athelstan, crowned in A.D. 924. He is lost in the mists of time, though many of his successors have left their mark.

The tyrannical and much-married Henry VIII, who ruled from 1509 to 1547, was the Tony Soprano of Tudor England, cross him at your peril. Before him, the fiendish Richard III (1483-1485) is thought to have put a hit on his nephews and was the last English king killed in battle. George IV (1820-1830) was a dandy who built a gaudy seaside palace and ate and drank his way into a 50-inch waist.

History is festooned with dozens of English, Welsh, Scottish and Irish royals — they are the stuff of Shakespearean dramas, Hollywood movies and Broadway plays. But at some point Wednesday, the incumbent sovereign, Queen Elizabeth II, will beat them all with a reign that will surpass in length the record of 63 years, 7 months, 2 days set by her great-great-grandmother Queen Victoria.

Third place, if you're counting, goes to George III, who lost the Thirteen Colonies and then his mind during his 59-year reign. The first Queen Elizabeth, the one with the pasty face and the orange hair, reigned for a little more than 44 years.

But this week's milestone is more than just the stuff of parlor games. Queen Elizabeth II is one of the rare human beings who have been on the world stage for as long as most of us can remember. (Only 1 in 5 Britons alive were around when she became queen in 1952.) During her reign, technological, political and social systems have changed beyond recognition. The world's population has grown from 2.6 billion to 7.3 billion.

Over 63 years and counting, she has advised a dozen prime ministers (the first was Winston Churchill) and observed 12 U.S. presidents and seven popes. She's still going strong, slowing a little, but it is not in her DNA to retire — i.e., abdicate in favor of Prince Charles. Her mother lived to 101.

Elizabeth has aged through the decades from glamorous princess to a somewhat dour, behind-the-times figure to a loving granny, but she has always been there, seemingly immortal and increasingly, yes, beloved.

At first, the queen did not want to mark the day (to be seen lording it over Victoria, whom she admires greatly), but has now decided to take a train journey with Scottish officials on a stretch of railway line reopened after many years. This seemingly bland gesture actually gets to the heart of Elizabeth's significance, argues Elizabeth biographer Robert Lacey. "It's invested with all sorts of meaning, and it's the most extraordinary example of the apparently passive but in fact very active role that Elizabeth plays in the psychology of her country," he said.

The success of Elizabeth's reign has not been in its length so much as in its nature, in how she has subsumed herself into the role. She has avoided personal scandal, has never confused fame with celebrity, has declined interviews and has shrouded both her private life and her political views.

In sum, she has heeded the advice of a Victorian political essayist named Walter Bagehot, who said that the monarchy must wrap itself in Oz-like mystery to remain precious. "We must not let in daylight upon the magic," he wrote in "The English Constitution."

Elizabeth, in the public eye for most of her 89 years, has kept us in the dark, magnificently.

"People actually know much less about the queen than they imagine," Lacey said. "But it seems to me that's less important than that people feel they know her very well."

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There are self-evident truths about Elizabeth. We know that she loves dogs — Labradors as well as corgis — and horses. One of her passions has been breeding and racing thoroughbreds. If you want to see her unguarded, joyful side, look up the video of her watching as her horse Estimate wins the Ascot Gold Cup in 2013.

What is less known: She has a prodigious memory for people and events, is a mischievous mimic, has enjoyed photography and jigsaw puzzles in her time, is a big fan of Scottish country dancing (think square dancing in kilts) and will clean up your dishes if you attend one of the royal family's summer barbecues at Balmoral Castle. She is also a deeply religious Christian but not evangelical, and observers say that she views her monarchy as a divine call, affirmed by her coronation oath in 1953.

Her sense of duty was undoubtedly also shaped by the missteps of her uncle — she was 10 when Edward VIII abdicated to marry the American divorcee Wallis Simpson in 1936, suddenly putting Elizabeth in direct line to the throne. Edward's brother and Elizabeth's father, George VI, was portrayed as the stammering good egg by Colin Firth in the 2010 film "The King's Speech."

The king's daughter has shepherded the institution so deftly for so long that the role and the person are indistinguishable from each other, said Philip Murphy, director of the Institute of Commonwealth Studies at the University of London.

"We have been lulled into this sense, because of Elizabeth, that constitutional monarchy in Britain is immutable," Murphy said, "and yet Britain is a country that cut off the head of one of its kings (Charles I) and got rid of another one (Edward VIII) less than a century ago. Like anything, it's fragile."

This seems hard to accept looking back at Elizabeth's life.

When the peachy Princess Elizabeth married the dashing Prince Philip in 1947, the wedding was as sensational in its day as Charles and Diana's in 1981 or William and Kate's in 2011. Churchill called it a morale-lifting "flash of color on the hard road we have to travel" after World War II.

In the 1960s, with the flowering of television and satire in England, the royal family began to be lampooned, gently. By the end of the Swinging Sixties, the staid royals thought that they should let some of the daylight in with a TV documentary called "Royal Family." It showed them as mortals, even if their speech and dress seemed to place them in the early 1950s.

The view today is that the documentary was a mistake, because it did precisely what Bagehot had advised against. It set the tone for an increasingly unfettered and insatiable tabloid appetite for the royal family, especially when the queen's sister, Princess Margaret, gained a reputation as a petulant jet-setter during and after the collapse of her marriage.

Media obsession with the House of Windsor reached its giddy depths in the 1990s, aided and abetted by a new generation of princes and duchesses whose behavior made such prime-time soaps as "Dallas" and "Dynasty" seem decorous by comparison. The marriages of three of the queen's four children failed, most notoriously when Prince Charles and Diana split amid squalid recriminations.

Whatever Elizabeth's private matriarchal stance over each catastrophe, she remained publicly stoic — too stoic after Diana died with her boyfriend, Dodi Fayed, in a car crash in Paris in 1997. Her death traumatized Britain and fostered a dark anti-royal mood not seen since the 1930s and the abdication. But Elizabeth woke up and smelled the PR disaster: She returned to London from Scotland, flew the flag at half-staff and addressed the nation and said nice things about Diana.

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It would have been hard then to imagine the queen being so venerated now, Lacey said. This national adulation was manifest during the rain-soaked river pageant that marked her Diamond Jubilee in 2012, and during the London Olympics that year, when Elizabeth went along with a James Bond spoof in which a double jumped out of a helicopter. That was followed by the queen entering the Olympic Stadium to a prolonged ovation.

Lacey sees several factors that have worked in her favor since the 1990s. For much of her reign, she was overshadowed by those around her. Her mother, a colorful and somewhat eccentric character, was the darling of the people and the media. Princess Margaret, the glamorous black sheep, was the tabloids' gift who kept on giving. Then as Margaret's publicity star faded, Diana's rose. Diana became known as the most photographed woman in the world. When her marriage soured and the palace sought to contain the damage, she portrayed herself as a victim, if not a prisoner.

"If Diana had not died, the monarchy would still be racked by the sort of discord that characterized her years," Lacey said. She would have been "sniping from the sidelines, having boyfriends, having husbands, who knows what. She was never going to go quietly."

And so the queen in her golden years is enjoying the sort of adoration not seen since she was a young woman. And perhaps it is now more profound.

"Everyone has grown up with the idea that Queen Victoria was the great 19th-century queen and, hey, presto, we have produced a modern Elizabeth Age," Lacey said. "Here's a woman whose achievements we can celebrate, and if you compare her to Queen Victoria, perhaps she's done a lot better."

"In the last decade or so," Murphy said, "there's a greater sense of admiration for her, even among people who call themselves republicans."

There are some obvious differences between Elizabeth and Victoria. The latter ruled when Britain grew into a world power with a broad colonial empire. Elizabeth has seen the recession of the United Kingdom — no longer imperial, uneasy in Europe and, with Scotland's independence movement, not even an internally secure union. (Elizabeth is also head of the Commonwealth, a 53-nation federation of former British dominions and colonies, and is the queen of 15 "realms" besides the United Kingdom, including Australia, Canada and Jamaica.) Victoria interfered politically with her prime ministers and, after the early death of her consort, Prince Albert, retreated greatly from her queenly duties.

But the two queens share uncanny similarities: Neither was destined to become the monarch, they both married German princes, they became creatures of routine and protocol, they loved horses and dogs, they survived gun-wielding youths, and they were women operating in a man's world.

From an early age, both decided to subordinate their lives to their country and steeled themselves mentally for this when barely into womanhood. In Elizabeth's well-known address from Cape Town, South Africa, on her 21st birthday, she said, "I declare before you all that my whole life, whether it be long or short, shall be devoted to your service."

On the day Victoria became queen at 18 in 1837, she wrote just as earnestly in her diary, "I shall do my utmost to fulfil my duty towards my country."

Reflecting on Victoria's 1901 death at 81, Lytton Strachey wrote, "The girl, the wife, the aged woman, were the same: vitality, conscientiousness, pride and simplicity were hers to the latest hour." The public, he said, had "felt instinctively Victoria's irresistible sincerity." The parallels are eerie.

Elizabeth will carry on as she has for more than six decades: spending late summer in Victoria and Albert's Scottish castle, returning to London for a working routine little altered since she was 25 — presenting honors to local worthies, offering private counsel to the prime minister, cutting the ribbon on the latest charitable asset, opening Parliament in full regalia, leading the nation's war remembrance on a Sunday in November at the Cenotaph in Whitehall.

If the ghost of Charles I haunts these precincts — he was executed in Whitehall in 1649 amid the English Civil War, leaving the country kingless for several years — he will discern that the English (and British) monarchy is well and truly restored.

"As long as Queen Elizabeth is still around," Murphy said, "the monarchy is safe."