The fashion industry lives on convincing you that something is new. The problem is that the summer wardrobe of the most photographed women of the twentieth century would pass down any street today without anyone blinking - and some of those photographs are seventy years old.

That is not a coincidence and it is not mysticism. Trends go round in circles, and what is sold today as a discovery, somebody already wore half a century ago. The difference is that those women were not buying a season - they were buying a shape that suited them, and then they did not change it.

Brigitte Bardot made capri trousers with ballet flats a fixture in the films of the fifties and sixties. She is also the woman who broke the wedding convention with a pink gingham dress at her 1959 wedding to actor Jacques Charrier. The check print has been coming back every summer since, usually presented as new.

Sophia Loren is remembered for the floral dresses of the sixties, which gave her what is hard to copy - lavish elegance with no attempt to look like anything other than what she was.

Jackie Kennedy is the author of the combination sold today under the label „quiet luxury”. A headscarf, oversized sunglasses, minimalism with the odd stronger piece. She was the first to make accessories the main part of a summer look rather than a decoration at the end.

Jane Birkin - yes, the Birkin the most expensive handbag is named after - actually introduced the woven basket into the summer wardrobe. Plus worn-in jeans, a white striped T-shirt and shoes you can actually walk in. The world's most famous handbag is named after a woman who carried a basket.

Grace Kelly travelled to Monaco at twenty-six with 80 suitcases. That is a number that says everything. She spent her summers in Seville, Corsica and Venice, in printed kaftans, linen sets, capri trousers, necklaces, scarves and wide hair bands.

Carolyn Bessette-Kennedy is proof that style survives everything. Almost thirty years after her death, her looks are being copied again - minimalist, clean, without a single piece that shouts.

Diana made the unexpected choices in the eighties: yellow outfits in a butter shade, blouses with small collars, red espadrilles. All three have been brought back to market this year as trends of the season.

What did they share? Not one of them dressed according to what was on offer that month. Each knew one silhouette and stuck to it. That is why the photographs still work today - and photographs from any seasonal campaign five years ago no longer do.