Was it his age? Her family? His army career?

Or was it simply that the relationship between Prince William and Kate Middleton had — like plenty of non-royal romances — run its course? Britain's Sunday newspapers suggested all of those as possible reasons for the future king's split with his girlfriend of four years.

Many of the stories were accompanied by photographs of the couple in happier times, but some also ran blurry shots of the 25-year-old Middleton as she left her family's home in the countryside west of London for lunch on Saturday.

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In seven pages of coverage and quoting unnamed sources, the Mail on Sunday said William, 24, decided to break up with Middleton because he "felt the fun had disappeared from their relationship." But the newspaper added that there was a belief among senior courtiers that Middleton's background wasn't royal material.

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"It sounds very snobbish but William's friends are all of a higher social ranking than Kate," the paper quoted an unnamed source as saying. "She is adorable, but ultimately she's just a middle-class girl from Berkshire."

The Sunday Times quoted an unnamed friend of the couple who said the split had nothing to do with William's British Army career — he is an officer in the Blues and Royals regiment of the Household Cavalry — or the media scrutiny they faced.

"The timing was wrong," the "close friend" was reported as saying. "Wills met her five years too early."

The paper also suggested Middleton will not tell her story to the media, despite having "the biggest kiss-and-tell in history," according to publicist Max Clifford.

"If she sold it she could make 5 million pounds [$10 million]," Clifford said. "But she wouldn't dream of doing it. She is loyal, trustworthy, discreet and proud. Selling her story is not in her vocabulary."

William's Clarence House office refused to comment Sunday.

The news of the split took many by surprise, especially those who believed any announcement from the couple would be news of an engagement, rather than of a breakup. But some of the Sunday newspapers said the strain had been showing for weeks, and cited photographs of William at nightclubs in the company of young women as a source of tension.

According to the tabloid News of the World — which devoted the cover and eight inside pages to the story, and called the split "the end of the fairy tale" — the breakup came after Prince William spoke with senior members of the royal family, including the Queen, Prince Philip, and Prince Charles. The Queen, who was reported to approve of Middleton, told William not to rush into marriage, the paper quoted a senior courtier as saying.

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