Originally, the Kingdom had an area of roughly 128,500 km2 and a population of approximately 3.3 million. The new state would be one of the smallest Polish states ever, smaller than the preceding Duchy of Warsaw and much smaller than the Polish–Lithuanian Commonwealth which had a population of over 10 million and an area of 1 million km2. Its population reached 6.1 million by 1870 and 10 million by 1900. The majority of ethnic Poles within the Russian Empire lived in the Congress Kingdom, although some areas outside its borders were also inhabited by strong Polish and Roman Catholic minorities.