In 2000, IWC introduced the cal. 5000 movement- a slow beat movement (18,000bph) with an extra large spring barrel giving it a 7-day power reserve. Thru the sapphire back you can view the heart shaped cam, which we all know indicates the famous Pellaton winding system from the cal. 8541 watches. This in-house movement, which took over four years to develop, was- I believe- the first to showcase the round gold Probus medallion on the rotor.
It was a true milestone, I believe, for IWC, for it took well respected traditions and innovations from IWC's history, and improved on them. The Portugiese 2000 watch was it's introduction, and one I believe might not be so well appreciated as it should be. I love mine- others out there?
Nelson