Kyiv (formerly Kiev) was the centre of the Rus principality in the 11th and 12th centuries and is still known as the Mother of Russian cities. The western Ukraine principality of Galicia was annexed by Poland in the 14th century. At about the same time, Kyiv and the Ukrainian principality of Volhynia were conquered by Lithuania before being absorbed by Poland. Poland, however, could not subjugate the Ukrainian cossacks, who allied themselves with Russia. Ukraine, except for Galicia (part of the Austrian Empire, 1772–1919), was incorporated into the Russian Empire after the second partition of Poland in 1793.