Princess Olga of Kiev and comparing ancient Bulgarian coins confirmed the deep and multilateral relations of Russia with Bulgaria in the old days. Somewhat unexpected is their manifestation even in the heraldic sign of Svyatoslav, pretty close to the mark Shishman, and especially to the sign of the son of the last - Bulgarian Tsar Peter. All this leads to a natural thought that perhaps there was a kinship with Svyatoslav Shishmanov dynasty. It turns out that such a hypothesis is put forward and discussed for a long time. We are met and rejected the arguments. But in the end it happened what happened to all the theories of the Russian-Bulgarian relations of that period: its 'forgotten'.