The following is a true story. The names have NOT been changed to protect the ridiculous.

The cover of this month’s Tatler magazine features a photograph of a beautiful 24-year-old Englishwoman, underscored by the playful subhead, “Harry loves Cressy.” Royal-watchers have reported that Prince Harry was recently seen snogging at a Swiss ski resort with Cressida Bonas, one of England’s most eligible bachelorettes. The two were introduced by Princess Eugenie, who is Harry’s cousin and Cressy’s best friend. Shortly thereafter, Cressy reportedly made the relationship “official” by inviting Prince Harry to the wedding of her sister Isabella and Sam Branson, the son of Sir Richard Branson, founder of the Virgin Group, which recently occurred in South Africa. The storyline has an added juicy twist in that Isabella – perhaps the most beautiful woman in England – was previously pursued by Harry’s brother Prince William, but she rejected him, and he finally gave up and married Kate Middleton instead.

If the reports are true, it’s a curious historical footnote to the line of Windsor. But, reading a little further, one notices that some sources describe the two girls as “sisters” while others use the more technically accurate “half-sisters.” Hmm…one asks oneself, “what’s up with that?”

And a deeper tale reveals itself. So let’s zip back to the beginning (and you may want to bring a pencil and notepad). Ready?

In 1947, a girl is born and is christened “Mary-Gaye.” She is the daughter of the 6th Earl Howe, Edward Richard Assheton Penn Curzon, and his second wife Grace Lilian Barker Wakeling. Her complete name is Mary-Gaye Georgiana Lorna Curzon. As she comes of age in Swinging Sixties London, Lady Mary-Gaye appears in a somewhat scandalous coffee table book, “Birds of Britain,” alongside Julie Christie, Sarah Miles and Lulu, and instantly becomes one of England’s “It” girls. Suitors come running, and in 1971 she marries Kevin Esmond Peter Cooper-Key. Together they have one daughter, Pandora Lorna Mary Cooper-Key. Following a divorce, she re-marries in 1977, this time to the impossibly-punctuated John Austen Anstruther-Gough-Calthorpe. Their marriage produces two daughters, Georgiana Moireach Gay Anstruther-Gough-Calthorpe and Isabella Amaryllis Charlotte Anstruther-Gough-Calthorpe, and one son, Jacobi Richard Penn Anstruther-Gough-Calthorpe. A second divorce leads to a third marriage, in 1988, to Jeffrey Bonas, and produces the simply-named and simply lovely Cressida Bonas. And finally, another divorce and a fourth marriage, to Christopher Shaw in 1996, produces neither children nor lasting happiness, as they later divorce.

Mary, mother of hyphens! How do the Brits keep this all straight? Well it’s all documented in Burke’s Peerage and Baronetage, currently in its 107th edition. And now it’s gone digital, so they can peruse the hoity-toity online – with a handy search function – at ThePeerage.com.

For the rest of us, here’s a simpler summary: M-G gets married four times and has five gorgeous kids, including two daughters named Bella and Cressy. Bella gets hit on by Wills. She turns him down, and marries Sam, so Wills marries Kate. Meanwhile, Cressy’s friend Eugenie introduces her to her cousin Harry, the brother of the guy who was previously chasing her sister. They are now kissing, in public! And should Harry and Cressy get married, everyone will be obliged to attend the wedding and smile awkwardly, while trying to remember who is who.

Jolly-good-fun, that!