Complex sentence: The later German (1916) and Polish (1919) censuses showed that Vilnius and its environs had a Polish majority, but these censuses and organisation of these censuses were heavily criticized by contemporary Lithuanians of the region as biased.
Split into simpler sentences: The later German (1916) and Polish (1919) censuses showed that Vilnius and its environs had a Polish majority. These censuses and their organisation were heavily criticized by contemporary Lithuanians of the region as biased.