Less than two years after Princess Anne of England married Mark Phillips in Westminster Abbey, she appears to have given up her kingdom for the horse. Phillips, a dashing captain in the First Queen's Dragoon Guards, is one of the empire's premier equestrians who won a team Gold Medal at the Munich Olympics. Anne, European champion in 1971, is as accomplished a horsewoman. Together the princess and her commoner husband have swapped the plumes and brass of the London court for a rusticated life of the tweeds and briars of the hunt in the English countryside. And since Anne, 24, has no realistic chance of ascending to the throne in the sexist line of succession (she ranks behind all three of her brothers and any of their male offspring), she and Mark are free to canter after their joint obsession of riding for Britain in the 1976 Olympics.

To win their spurs, Anne and Mark are competing on the international circuit. Thus their first visit together to the U.S. this week is not for pomp or ceremony. It is to rally with the horsey set at the three-day U.S. Open Championship in the genteel Massachusetts Tory country just 25 miles north of the site of the Boston Tea Party.

Regardless of their competitive performances, Anne and Mark also will be judged on how they "sit" with the media. Before marriage Anne was rated by her subjects as perhaps the least popular of the large royal clan. On ceremonial occasions (she still suffers through about two a week), Anne is hard pressed to conceal her boredom. Her habit of training her horses in blood sports like fox hunting have brought vilification from Parliament's back benches. Like Prince Philip, she makes it clear that reporters give her a royal pain—but, unlike Dad, she lacks a saving quip. Once, flipped frighteningly by a horse, she snapped to reporters, "I'm sure you're disappointed that I'm not seriously hurt."

Mark, 26, is considerably more amiable than his imperious wife. Yet when an overly aggressive female photographer crowded his steed during his last visit to the States, he booted the plebeian in the stomach. Later he asked someone to apologize for him.

The English army has conveniently posted Mark as an instructor at Sandhurst, the royal military academy. He and Anne kick around in a 12-room Georgian manor with their two dogs, a live-in butler and cook, a gardener, her secretary (a major, senior to Mark), two ladies-in-waiting and round-the-clock guards. (Last year an unemployed worker shot up their limousine in an unsuccessful kidnap attempt.) They pay a pittance of $20 in weekly rent, even though Anne's governmental allowance of $84,000 exceeds the salary of Prime Minister Harold Wilson by $36,000. (Mark draws $6,625 a year as a captain.)

Mark and Anne are waist-watchers (she's 110 pounds) who stick to a stolid, spice-free diet of roasts and vegetables, generally imported from the London food spa Fortnum & Mason, except when Anne forays into the village for bacon and eggs. A "behavior directive" at Sandhurst proclaims that anyone meeting Captain Phillips' wife will be "presented," not introduced, and address her as "Ma'am." Still, Mark and Anne exchange spots of tea with other officer couples and recently dined with two cadets and their parents. Mark, who wears contact lenses, works out with the rugby squad. To test the cadets, Anne was once asked to try to smuggle three rifles past the guards in her purple Scimitar sports-car. (She did not succeed.)

Always proper except for her language, which is enlivened with favorite epithets like "bloody" and "bugger," Anne does not smoke, drinks nothing stronger than Coke and usually beds in by 10 p.m. She orders two custom-cut outfits a month, and even though her couturiere says her perfect size 10 "is a joy to fit," Anne is still wearing the staid frocks and sensible shoes that doomed her mother, Queen Elizabeth II, to the worst-dressed list. Anne's hat-maker says, "She never minds her hairdo. She just bungs her hair inside her hat and, wallop, that's it." Generally, Anne prefers the company of men to women, and two of her closest confidants are racing driver Jackie Stewart and his wife, Helen.

Though her older brother, Prince Charles, was educated at Cambridge to be the future king, Anne has never been bookish. Instead she says, "I was gently nudged into riding at the age of 2." When she blurted to a BBC interviewer that a university education is "a very much overrated pastime," the palace snipped the offending crack from the TV tape. She graduated from Benenden, a little-known boarding school and was romanced on horseback by a half-dozen suitors. Anne's favored dates would usually escort her to a dinner party for four and then rendezvous with her in a secluded flat, while a policeman would loyally wink off outside in her limousine.

She met her horseman husband-to-be at a reception for Olympic equestrians. The son of socially ambitious country gentry from the West Country village of Great Somerford (his father, a director of a pork-sausage company, was recently superannuated), Mark went to Marlborough, a boarding school where the headmaster judged his scholarship "not outstanding." (Insiders at Buckingham Palace have code-named Mark "Fog," as in "dreary and dense.") Though he failed to gain admission at first, he eventually won his appointment to Sandhurst, where he so excelled at riding that in 1968 he was the first cadet chosen for the Olympics. Reportedly, Queen Elizabeth hesitated to approve Mark as her future son-in-law because of rumors of muscular dystrophy in his family, but Anne and Mark both passed exhaustive medical tests and were soon back on the bridal path.

Anne has told her parents that she plans at least two children, but not until after the Olympics and Mark musters out of the army in five years. Mark's father says that "whatever they do, it will be something with horses." Few doubt it. When actor Peter Ustinov met Anne at a reception, he said, "I haven't met your husband." "Oh," replied Anne. "Mark? Mark?" When there was no answer, she made a clucking noise, as if to a horse. In a second the royal consort was at her side.