Hey, don't copy my style.  

I spent quite a bit of time researching the true world premiere year for Clouds of May. You mentioned 1998, which isn't listed a lot but I've seen it before. Mostly, it's 1999, which is what Artificial-Eye has used. But on Ceylan's official site, it's noted that the film had its WP at the 2000 Berlinale. That said, the site also uses 1999 at other points. But at a recent retro, 2000 was the year catalogued by Mr. Quandt, and that pretty much solidified my stance.