The Patek Philippe Nautilus is the most iconic luxury sports watch of the twentieth century and arguably the most sought-after pre-owned timepiece in the world today. Designed by Gérald Genta and introduced in 1976 as ref. 3700/1A, the Nautilus drew inspiration from a porthole, its rounded octagonal bezel and integrated horizontal-striped dial immediately establishing a new visual language for the luxury sports watch. It was audaciously priced in steel at the time of its launch, a statement of confidence from Patek Philippe that proved thoroughly justified over the following decades. The original 3700 remains one of the most valuable and rare pre-owned Nautilus references. Its successors — the 3710, 3800, 3710, 5711/1A, 5712, and the women's 4700 and 7010 lines — progressively refined the design while preserving Genta's foundational vision. The ref. 5711/1A in stainless steel, discontinued in 2021, became the defining secondary market Nautilus, with pre-owned prices consistently commanding multiples of retail. The 5726A with annual calendar and moonphase, and the 5980 chronograph, are among the most technically accomplished pre-owned Nautilus references. DeMesy & Co. in Dallas has been authenticating pre-owned Patek Philippe Nautilus watches since 1987.