Existing sources dated to the Saint Sophia Cathedral only vague. If one do not resort to stretches, fantasies and source distortions, one can say that Saint Sophia Cathedral in Kiev is a monument of 2 quarter of 11th century. Detailed chronology of the cathedral construction can not be established. All attempts to refine the proposed date to some closer intervals are essentially equivalent – they all have no support in specific sources.
As for anniversaries more narrow date is needed, one should stay in the year 1037:
1. This date is still read in all the ancient chronicles (Laurentian, Hypatian and Novgorod first – senior version);
2. At this date the most detailed story posted about the initial history of the cathedral;
3. This story established view on the Kyiv St. Sophia as a national (and beyond – and superethnical) religious and cultural center.
So, in 2037, real and not false millennium of St. Sophia Cathedral can be celebrates. So if UNESCO survive to that time, this year will be proclaimed as the year of the Kyiv Sophia as monument of world importance.