Hi Tatiana,
I was just posting in the Polish Culture forum where Jaga has started a very interesting discussion about the root of Lechistan/Lahistan/Lehistan by which Poland is known in some countries. I found a small paragraph on wikipedia which I have pasted below.
Have you heard anything of this legend in Russia? If so, could you give me more details. If not, I would love to hear of other famous Russian myths and legends.
Legend of Lech, Czech and Rus
According to legend, three brothers named Lech, Czech and Rus were exploring the wilderness to find a place to settle. They came across a hill with an old oak and an eagle on top. Lech took the white eagle as his emblem and around the oak he built a stronghold, and because of the eagle nest, called in Polish a gniazdo, he called the stronghold Gniezdno, which in modern Polish is spelled Gniezno. The other brothers went further on to find a place for their people. Czech went to the South to create the Land of Czechs, and Rus went to the East to create Rus'.