pocketwatches, and the development of the wristwatch in the early part of the 20th century. Conceived in its original form by IWC at the behest of two Portuguese businessmen who desired an exceptionally accurate wristwatch, the IWC Portuguese watch collection has grown over the decades to encapsulate a whole range of elegant and boldly dimensioned mechanical timepieces which have disproved the generalization that large watches cannot be classically beautiful. These exceptional timepieces also demonstrate IWC's great acheivements as a manufacturer of haute horlogerie, and present such horlogical masterpieces as the tourbillon, the minute repeater, and perpetual calendar with dual-hemisphere moonphase display. These exceptional Portuguese watches are often enriched with unique IWC technical elements, such as the moonphase display of the Portuguese Perpetual Calendar watch, which errs only a single day every 577.5 years.