The capital was located in Warsaw, which towards the beginning of the 20th century became the Russian Empire's third-largest city after St. Petersburg and Moscow. The moderately multicultural population of Congress Poland was estimated at 9,402,253 inhabitants in 1897. It was mostly composed of Poles, Polish Jews, ethnic Germans and a small Russian minority. The predominant religion was Roman Catholicism and the official language used within the state was Polish until the failed January Uprising when Russian became co-official as a consequence. Yiddish and German were widely spoken by their native speakers.