The article below has been written by Farroukh Jorat and first appeared in Fravahr.org.
In the early Middle Ages (III-X centuries AD) Eastern Slavs contacted with Baltics in the north, with Germans in the west and with Eastern Iranians in the south-east. Interaction of the Eastern Slavs to the Iranians left their mark on the languages and in the religious culture of the East Slavic peoples (Russians, Ukrainians and Belarusians). Let us consider some of the elements of the ancient culture of the Eastern Slavs with Iranian origin.
In 980 in the “Tale of Bygone Years” (Povest vremennykh let) in the list of gods, which were revered in Kiev, was noted deity Semargl. Researcher Vasily Abaev believed that the name of this deity origin from Zoroastrian Simurg. Word Semargl borrowed into the Old Russian language from the Scythian and had the original form Senmarγ .
Simurg is the mythological character, combining the traita of dog and bird (Old Iranian Saena mərəγo, “dog-bird”). Russian historian Boris Rybakov believed that the images of winged hounds in the art of ancient Russia represent the image of Semargl .
In 1873 in Glazov county of Vyatka province was discovered a silver dish with the image of Simurg. It was manufactured in the VIII century AD in Iran or Central Asia. After the adoption of Christianity in Rus in 988 image of Semargl has been replaced and forgotten.
In the “Instructions” (Pouchenia) of Vladimir Monomakh (1053-1125) is a mention about mythical southern country Irey, where the birds fly away in winter and identified with paradise. The most convincing etymology of the word irey is from Old Iranian *airuā-(dahyu-) “Aryan land”. Apparently, this word was borrowed by the Eastern Slavs from Sarmatian tribes. A similar parallels also observed in the language of the Sami, one of the Finno-Ugric Peoples of Russia: Årjel “south”, år’jān “far to the south”, Old Sami *orja “South”.
In the “The Tale of Igor’s Campaign” (Slovo o polku Igoreve) (end of XII century) mentioned div as demonic character, sitting on a tree and his whistle presaged the failure of the campaign of Prince Igor at Cumans. The image associated with the Devas — the servants of Ahriman from Zoroastrian mythology.
Dahl VI in his Explanatory dictionary … noted about one of the meanings of Russian word div: “ominous bird, probably an owl”. From this we can conclude that the prototype image of div in the Eastern Slavic culture is owl with a sinister reputation of foreboding.
 Abayev VI. Scythian-European Isogloss. At the crossroads of East and West. (Skifo-evropeyskie izoglossy. Na styke Vostoka I Zapada). In Russian.
 BA Rybakov. Paganism of Old Slavs. (Yazichestvo drevnikh slavian). In Russian