Long before the first cover girl's face appeared on the front of a magazine or the 'It Girls' of Hollywood graced silver screens across the world, we looked to royalty for their beauty secrets. After all, if Helen of Troy's stunning visage was capable of launching a thousand ships, she must have been doing something right - for the record, some say that she bathed her face in a solution of water and vinegar every evening, while others put it down to the honey and olive oil present in so many Ancient Greek cosmetics at the time.

Cleopatra, meanwhile, was famously said to have taken long, languid soaks in a bath of milk and rose petals, which no doubt played a part in the Egyptian queen's ability to ensnare two of the most powerful men in the Roman Empire. Around the same time that Mary, Queen of Scots was bathing in heated sweet white wine to preserve her youthful appearance, Catherine de' Medici, an Italian noblewoman who became the Queen of France between 1547 and 1559, went about creating a makeup revolution across the land through the introduction of face paint made of white lead and vermillion.

Rather more appealingly, she also turned to the Florentian pharmacy, Santa Maria Novella - which is still in existence today - to create the first eau de cologne for her, a blend of citrus and bergamot-scented water that was named 'Water of the Queen'. By wearing it throughout her reign and passing it to her friends and confidantes, the perfume became enormously popular throughout France for an impressive 300 years - a prime example of a royal figure making a serious beauty statement for all and sundry to follow.

In today's camera-saturated environment, where trends change in the blink of an eye and the glare of the paparazzi flashbulbs continues in its relentlessness, it's hard for a modern queen or princess to stay on top of their beauty game. Neither does it help that Disney's cartoons have immortalised the image of the fairytale princess in a ballgown, with flawless skin and hair that dances silkily in a conveniently timed gust of wind. You'd never catch Aurora with sad, sagging eyebags from lack of sleep (well, duh), just as you'd be unlikely to come across Ariel with panda eyes because she forgot to use waterproof mascara.

In short, a princess is always immaculate, no matter the occasion. Diana Mather, Director of Training at The English Manner, which specialises in contemporary etiquette tuition, outlines the characteristic look of a classic, modern day princess: "Hair must be tidy and well styled. Makeup should define the features, but not be too heavy. A good diet and skincare routine also helps give a look of health and vitality. Perfect posture is essential - all members of royalty should sit, stand and walk with grace and elegance - but the most important thing for any princess is a beautiful smile!"

Ironically, despite the fact that they're so visible to the public eye, princesses are often required to practise an enormous amount of discretion, even when it comes down to revealing their grooming tips. Unlike your run-of-the-mill A-Lister, who still has the freedom to Instagram or blog (see: Gwyneth Paltrow) about the contents of their bathroom cabinets, members of royalty tend to prefer to keep things professional, rather than up-close-and-personal. We're restricted to admiring them from a distance - which is, in turn, what makes their beauty secrets all the more intriguing.

Where there's a will, there's a way, however. The most minute details of the Duchess of Cambridge's wedding look in 2011 - from her nail polish (a mix of Bourjois' Rose Lounge and Essie's Allure, for the record) to the perfume she was wearing (Illuminum's White Gardenia Petals) - were swiftly circulated to aspiring 'copy-Kates', while her glowing appearance shortly after the birth of Princess Charlotte was quickly attributed to Bobbi Brown's Brightening Finishing Powder and the skilled of hairstylist Amanda Cook Tucker. 

Sales figures for Heaven Skincare's anti-ageing Bee Venom Mask and Silk Skin tinted moisturiser also shot through the roof when it was somehow revealed that the Duchess of Cambridge had been introduced to the brand by her mother-in-law, the Duchess of Cornwall, while appointments at Richard Ward's salon - where Kate has her trademark glossy brown locks cut and coloured on a regular basis - have to be secured months in advance. The same rule also applies to nail maestro Marina Sandoval, who uses her very own recipe of natural oils from South America to keep the Duchess' nails pristine.   

Other members of royalty have also let slip the names of a few of their go-to beauty gurus: Princess Tatiana of Greece and Denmark is an enormous fan of Antonia Burrell's holistic and chemical-free facials, while Mary, Crown Princess of Denmark appropriately turned to Danish skin cosmetician Ole Henriksen to maintain a healthy Scandinavian complexion (Ole's Fresh Start Eye Crème being one star product). Mette-Marit, Crown Princess of Norway relies on Swedish colourist Mirjam Bayoumi to keep her blonde hair looking as fresh and bright as corn silk - despite the fact that Bayoumi's salon is based in the United States.  

It might all sound like fun - having access to the world's finest makeup artists, manicurists and hairstylists, but again, Diana Mather is quick to remind us of the extreme levels of scrutiny that princesses face: "Hair always has to be well brushed and tidy, and makeup is supposed to be flawless in case they meet members of the public or are required to have close-up photos taken by photographers. Hair shouldn't blow across the face when attending outdoor events, and should look sleek and shiny if no hat is worn. Too much makeup isn't appropriate as a natural look is what is required. And like all ladies, they have to make sure there is never any lipstick on their teeth!"

Ultimately, taking on a royal role means bringing your A-game to the table every day, even under immense pressure - so who better to source reliable, error-free beauty tips from than the modern princesses? They're human, just like us, but they've been disciplined enough to master the art of never having a single hair out of place. Respect to that, bow down.

Picture-perfect Royals