Vintage Cartier Open Heart Trinity Necklace Set in 18k Rose, Yellow & White Gold

Love, fidelity and friendship: the three principles that inspired Louis Cartier (1875–1942) — grandson of Cartier founder Louis-François Cartier — to design the intertwined Trinity ring in 1924, with pink, yellow and white bands to signify each tenet, respectively. And, in the same way that some of the most effortlessly chic of style icons will throw a wedding band on a chain and wear it around their neck, the legendary French jewelry house has since then presented the beloved ring as the Trinity necklace, where it makes a symbolic and elegant statement against the wearer’s neckline.

Legend has it that the Trinity was born of a request from the French writer and artist Jean Cocteau, who challenged Louis Cartier to devise a ring based on Saturn’s celestial ones. Cocteau would go on to wear a pair of them on his pinkie. (In 2010, Cartier honored Cocteau with a new six-banded ring in homage to his original look.) For Louis Cartier, the Trinity was a triumphant exercise in simplicity, an icon born of a stunningly understated premise: an unadorned gold band. Looping three of them together — in the maison’s three colors of 18-karat gold — Cartier created a now-legendary accessory that is enduring in its appeal.

The Trinity necklace is proof of that timelessness, a new riff on a beloved design. Much like the vintage Cartier Trinity rings that garner attention from collectors and admirers alike, it has been interpreted in a myriad of ways: In addition to the classic tricolor ring secured by a delicate double chain on either side, Cartier has released versions topped with solitaire diamonds, tied with cord, hanging on double or triple chains and with rings rendered in diamond-encrusted platinum to name a few.

In 2012, Kate Middleton, Duchess of Cambridge (wife to England’s Prince William), wore an elongated iteration of Cartier’s Trinity necklace featuring three sets of Trinity rings — one diamond-studded oversize version flanked by two smaller side rings — connected by a bundle of gold chains. The piece was rumored to be worth upward of $70,000 and was the subject of much media coverage. But, like the best designs, Cartier’s Trinity necklace doesn’t need much added flair — it’s just as stunning at its most simple.

For its extraordinary range of bracelets, watches, rings and other adornments, French luxury house Cartier is undeniably one of the most well known and internationally revered jewelers in the world among clients both existing and aspirational.

Perhaps 1847 was not the ideal time to open a new watchmaking and jewelry business, as the French Revolution was not kind to the aristocracy who could afford such luxuries. Nevertheless, it was the year Louis-François Cartier (1819–1904) — who was born into poverty — founded his eponymous empire, assuming control of the workshop of watchmaker Adolphe Picard, under whom he had previously been employed as an assistant. Of course, in the beginning, it was a relatively modest affair, but by the late 1850s, Cartier had its first royal client, Princess Mathilde Bonaparte, niece of Napoleon Bonaparte, who commissioned the jeweler to design brooches, earrings and other accessories.

Under the leadership of Louis-François’s son, Alfred, who took over in 1874, business boomed. Royalty around the world wore Cartier pieces, including Tsar Nicholas II of Russia, the Maharaja of Patiala and King Edward VII, who had 27 tiaras made by the jewelry house for his coronation in 1902 and issued Cartier a royal warrant in 1904. (Today, the British royal family still dons Cartier pieces; Kate Middleton, Duchess of Cambridge, regularly sports a Ballon Bleu de Cartier watch.)

Cartier’s golden years, however, began when Alfred introduced his three sons, Louis, Pierre and Jacques, to the business. The brothers expanded Cartier globally: Louis reigned in Paris, Pierre in New York and Jacques in London, ensuring their brand’s consistency at their branches across the world. The trio also brought in such talents as Charles Jacqueau and Jeanne Toussaint.

One of Cartier’s earliest major successes was the Santos de Cartier watch — one of the world's first modern wristwatches for men. (Previously, a large number of people were using only pocket watches.) Louis designed the timepiece in 1904 for his friend, popular Brazilian aviator Alberto Santos-Dumont, who wanted to be able to check the time more easily while flying.

Cartier’s other famous timepieces include the Tank watch, which was inspired by the linear form of military tanks during World War I, and the so-called mystery clocks. Invented by watchmaker and magician Jean-Eugène Robert-Houdin and later crafted exclusively for Cartier in the house’s workshop by watchmaker Maurice Couët, the mystery clocks were so named because the integration of glass dials on which the clocks’ hands would seemingly float as well as structures that are hidden away within the base give the illusion that they operate without machinery.

On the jewelry side of the business, Cartier’s internationally renowned offerings include the Tutti Frutti collection, which featured colorful carved gemstones inspired by Jacques’s trip to India and grew in popularity during the Art Deco years; the panthère motif, which has been incorporated into everything from brooches to rings; and the Love bracelet, a minimal, modernist locking bangle inspired by medieval chastity belts that transformed fine jewelry.

While the Cartier family sold the business following the death of Pierre in 1964, the brand continues to innovate today, renewing old hits and creating new masterpieces.

Find contemporary and vintage Cartier watches, engagement rings, necklaces and other accessories on 1stDibs.