Why did the map of eastern europe change so frequently for so many years?
answer in complete sentences, using proper grammar, and accurate spelling.

It changed so much because there were always European explorers heading out on voyages, for many reasons (like to trade with neighbouring countries, ferrying people from one land to the other, etc). During those voyages they found new lands, and so the maps had to be revised quite often because of these new discoveries.

Except common history