Poland was once empire. From 1619 till 1667 Polish territory was about 1million of square kilometers. It was the biggest country in Europe! However Poland was also entirely erased from the maps. It was in 1795 - 1918. Yes, just before the First World War Poland existed only in memmories and hearts of Poles. This lasted more than 100 years! It is extraordinary, that Polish nation, after such long non-existence, managed to force 'Europe' to recreate Poland once again. To see how Polish borders have been changing through the time see video below.

Polish borders from 990 - 2008

Another video showing Polish borders through the past