Popular with the aristocracy and the royals in the 18th and 19th centuries, the lavish festivity will be held for tourists.
Officially, Alexander I died of typhus aged 47 on 1 December 1825, but evidence suggests he faked his demise and lived as a holy man.
New handwriting analysis suggests Royal's death was faked so he could repent his sins as holy man.
Tsar's daughter may, after all, have escaped the execution which wiped out the royal family, says new book.
President Putin opened his visit to Buryatia by going to Ivolga Datsan, the main monastery of the Buddhist Traditional Sangha in Russia.