Vladimir Stasov
One theory (Vladimir Stasov, 1868) is that the legend was an adaptation of the exploits of Rostam, hero of the Persian epic "Shahnameh". Possibly this story was introduced by the Turkic (Tatar). One of the similarities is the combat between father and son, Rustem and Sohrab, although this has parallels worldwide. Another is Rustem's campaign, in Mazandaran for the release of the Persian king Kay Kaus.