Somewhere in the English countryside, a young lady is curling up with a book and a picnic basket for what will surely be a day of reflection. As the sun begins to settle and the birds to calm, she will consider the meaning of love and marriage, and decide if she should follow the advice of the famous English historian Edward Gibbon and marry for love or for money.

This is the story of Uma Thurman and Robert Pattinson, arguably the most famous couple in history — at least, among those who closely follow the celebrity news of the day. Together for over 20 years now, they have been photographed on the red carpet more times than one can count. Their wedding celebration was one of the most memorable celebrations of the year. They are the poster children for the modern-day couple. They are loved and loathed in equal measure, and their every move is dissected and analysed by an obsessive public.

Why have they stayed together for so long? This is not a question that can be easily answered, but there are a number of reasons why this unlikely union has not only survived, but thrived, particularly in the public eye.

They Are Ambiguous Characters

To begin with, one must acknowledge that, in the public eye, this celebrity couple is almost archetypically ambiguous. The 54-year-old actress is famous for her striking looks and saucy on-screen characters. She often dresses in provocative outfits and has more than a few scandals tucked away in her past. There is no doubt that she has held on to her mania for adventure and taken him with her on a number of high-profile escapades. From the get-go, it was never entirely clear whether she was playing the dainty damsel in distress or the courageous heroine. In the most recent Batman v Superman: Dawn of Justice, she plays the role of the tyrannical, Manichean Darkseid with an assured charm and a hint of Marilyn Monroe about her.

In a similar vein, Robert Pattinson is known for his brooding looks, which have enticed a legion of female fans in his direction. The British actor has been involved in a number of high-profile romances, and has famously dated actress Kristen Stewart. While it is easy to see why these two polar opposites have found each other — their shared background as descendants of Scotland’s great inventor, James Watt, ensures that they will forever be locked in an uneasy battle of wills — it is less clear why they have remained together for so long. Was it just attraction at first sight? Did they meet while shooting a film together and immediately click? We may never know.

They Are Vivid Characters

Another reason this celebrity union has persisted is that they are vivid, well-defined characters. Both are very intelligent people who have thought long and hard about the nature of love and commitment. In their time away from the cameras, they have written books about their philosophies of life and love. Despite their different upbringings and life experiences — Uma is the daughter of film legend, Warren Beatty, and Hollywood heiress, Lois Geller, while Robert comes from a relatively modest background in Wales — they have a great deal in common. Both are survivors, and their relationship has weathered a number of storms. They are keen students of human nature and the travails of romantic relationships, and have sought to apply these learnings to their own personal life together. As a result, their characters are instantly recognisable, and they have become cultural and literary figures in their own right.

They Are Entertaining

These two are also, more than anything, entertainers. They enjoy each other’s company, and have a great deal to say about life and love that is both thought-provoking and, at times, hilarious. Their Instagram stories are often laced with wit and whimsy, and they have an entire website devoted to fun, frivolous posts. Why should one read Beowulf or Gibbon when one can enjoy some old-fashioned comic relief alongside cutting-edge feminist commentary? Why should one study the great works of western literature when one can be entertained by the exploits of the colourful, famous, and sometimes troublesome individuals who populate these works? Their celebrity has not gone to their heads, and they remain grounded, intelligent, and entertaining individuals. For those who love a good drama, the couple are iconic fixtures of the red and glossy magazine covers, but for those who like their articles to have some bite, they are a font of entertainment as well.

They Are Modern Day Love-at-First-Sight Scenarios

This is a question that has been asked a lot over the years, particularly since their separation in 2013. While they may have started out as cinematic opposites — a brooding, anti-hero versus a voluptuous, temptress — they have proven time and time again that opposites do indeed attract. Perhaps, it is their shared background as descendants of Scotland’s great inventor that has led them to each other. In any event, their is a wealth of romantic imagery on social media that would put a blush on any cheek. Their fans often joke that they were meant to be, a sentiment that they have themselves adopted. They have become iconic figures not just for their beauty and sexuality, but for their matchmaking skills as well.

They Understand Modern Love

This is not to say that Uma and Robert understand modern love especially well. They are, after all, actors, and as such, they have played many parts in many films. What is certain, however, is that they have made a concerted effort to understand and embody the traits of a modern, progressive couple. For Uma, the decision to remain with Robert was an easy one. She knew that they shared a common interest in literature and that he had the makings of a good character. They also both enjoy a good joke, and their sense of humour and creativity has certainly helped them to keep their marriage interesting. Indeed, there is a sense in which their enduring partnership can be seen as a commentary on the changing nature of romance and commitment. While they may not always see eye-to-eye, they are open-minded and pragmatic, and have never been afraid to express different ideas and perspectives. They may argue, but they do so with an open and creative mind. The only constant in their turbulent relationship has been their mutual, lasting love.