Hans Wilsdorf had a mission in mind when he founded Rolex in 1905: to craft the first wristwatch robust enough to maintain accurate timekeeping in rigorous physical conditions.

Just five years later, he met his accuracy target when a Rolex wristwatch was awarded a certificate for chronometric precision by the Official Watch Rating Centre in Bienne, Switzerland, placing his timepiece on par with its pocket-watch predecessors.

In 1926, Wilsdorf realized his founding dream by introducing the Oyster, the world’s first water- and dust-proof wristwatch that kept accurate time reliably, whatever the environment.

Before the Oyster, horologists had attempted various methods of making a wristwatch waterproof and dustproof, including double-casing the timepiece and other unwieldy options.

For the new aptly named Oyster, Wilsdorf devised a system of screwing the watch’s caseback, bezel and winding crown to its middle case, rendering it impervious to dust and water. And he wanted to prove these achievements to the world.

The visionary watchmaker identified an opportunity just a year later in 1927. That’s when he gave long-distance swimmer Mercedes Gleitze, who was attempting to become the first British woman to swim across the English Channel, an Oyster to wear while tackling the grueling 10-hour-plus journey.

When she reached the shore and emerged from the water victorious, the Oyster was keeping perfect time. Gleitze’s feat was an international press sensation. The next day, Wilsdorf took out an ad in a London newspaper featuring a photo of Gleitze wearing her Oyster, introducing his waterproof watch to the world and cementing its place in history.

Not one to sit on his laurels, Wilsdorf achieved another first in 1931 by inventing the Perpetual rotor, a self-winding system that could power the watch continuously without a need for manual winding.

Wilsdorf equipped the Oyster’s movement with his system, and from then on, the word Perpetual was added to the Oyster name on the watch’s dial. Nearly all of Rolex’s timepieces have the prénom Oyster Perpetual — the Oyster Perpetual Submariner, Land-Dweller and Air-King, among others.

Over its 100-year lifetime, the Oyster has evolved as Rolex continued to improve on its movement and design, and the brand has produced dozens of iterations. Most Rolex watches today have modern versions of the Oyster case and “Oyster Perpetual” on the dial. And updated versions of the original Oyster Perpetual as a time-only piece continue to this day.

To celebrate the milestone anniversary, Rolex introduced two models in the Oyster Perpetual collection this year.

The new Oyster Perpetual 41 timepiece is crafted from the brand’s proprietary Oystersteel and yellow gold. In a first for the Oyster collection, the two-tone timepiece, which has a yellow gold bezel and crown, is fitted with an all-steel bracelet rather than a steel and gold bracelet.

The new Oyster Perpetual 36 features a multicolored dial in the brand’s iconic jubilee pattern. According to Rolex, the Oyster Perpetual 36’s dial “celebrates the inventiveness of the brand and its dial-making artistry.”

At 100 years young, the Oyster deserves a celebration.