There is an indication of the place names of many countries in Eurasia, which may partly be not only similar in sound, but also united by common Indo-European languages: Varanasi, Varna, Verona, Brno, etc. A comprehensive scientific analysis was conducted in 2015–2016 by the historian Pavel Popov. His conclusion: "Voronezh" is a probable Slavic macrotoponym associated with outstanding signs of nature, has a root "voron-" (from the proto-Slavic "vorn") in the meaning of "black, dark" and the suffix "-ezh" "(-azh, -ozh"). It was not “transferred” and in the 8th - 9th centuries it marked a vast territory covered with black forests (oak forests) - from the mouth of the Voronezh river to the Voronozhsky annalistic forests in the middle and upper reaches of the river, and in the west to the Don (many forests were cut down). The historian believes that the main "city" of the early town-planning complex could repeat the name of the region – Voronezh. Now the hillfort is located in the administrative part of the modern city, in the Voronezh upland oak forest. This is one of Europe's largest ancient Slavic hillforts, the area of which – more than 9 hectares – 13 times the area of the main settlement in Kiev before the baptism of Rus.  Folk etymology claims the name comes from combining the Russian words for raven ("ворон") and hedgehog ("еж") into "Воронеж". According to this explanation two Slavic tribes named after the animals used this combination to name the river which later in turn provided the name for a settlement. There is not believed to be any scientific support for this explanation. In the 16th century, the Middle Don basin, including the Voronezh river, was gradually conquered by Muscovy from the Nogai Horde (a successor state of the Golden Horde), and the current city of Voronezh was established in 1585 by Feodor I as a fort protecting the Muravsky Trail trade route against the raids of the Nogai and Crimean Tatars. The city was named after the river. In the 17th century, Voronezh gradually evolved into a sizable town. "Weronecz" is shown on the "Worona" river in Resania in Joan Blaeu's map of 1645.