Lithuanian and Polish rule
By the middle of the 14th century, Ukrainian territories were under the rule of three external powers—the Golden Horde, the grand duchy of Lithuania, and the kingdom of Poland.
The steppe and Crimea, whose coastal towns and maritime trade were now in the hands of the Venetians and Genoese, formed part of the direct domains of the Tatar Golden Horde. This was the westernmost successor of Genghis Khan’s Mongol empire, whose khan resided at Sarai on the Volga River. By the mid-15th century the Golden Horde was in a process of disintegration. One of its successor states was the Crimean khanate, which after 1475 accepted the suzerainty of the sultans of the Ottoman Empire. Both the Crimean Peninsula and large areas of the adjoining steppe continued under the khanate’s rule until its annexation to the Russian Empire in 1783.
Elsewhere in Ukraine, Mongol rule was largely indirect, limited to exactions of taxes and tribute whose collection was delegated to the local princes. It was also relatively short-lived; northwestern and central Ukraine became an arena of expansion for a new power that had arisen in the 13th century, the grand duchy of Lithuania.
Having already over the course of a century incorporated all the lands of Belarus, Lithuania under Grand Duke Algirdas advanced rapidly into Ukraine. In the 1350s Chernihiv and adjacent areas—and in the 1360s the regions of Kiev and, to its south, Pereyaslav and Podolia (Podillya)—were occupied by Lithuania. Competition with Poland over the former Galician-Volhynian principality ended in the 1380s in partition, by which Lithuania gained Volhynia and Poland was confirmed in its possession of Galicia. Thus, Lithuanian control extended over virtually all the Ukrainian lands as far as the open steppe and even, briefly, to the Black Sea.
Within the grand duchy the Ruthenian (Ukrainian and Belarusian) lands initially retained considerable autonomy. The pagan Lithuanians themselves were increasingly converting to Orthodoxy and assimilating into Ruthenian culture. The grand duchy’s administrative practices and legal system drew heavily on Slavic customs, and an official Ruthenian state language (also known as Rusyn) developed over time from the language used in Rus.
Direct Polish rule in Ukraine in the 1340s and for two centuries thereafter was limited to Galicia. There, changes in such areas as administration, law, and land tenure proceeded more rapidly than in Ukrainian territories under Lithuania. However, Lithuania itself was soon drawn into the orbit of Poland following the dynastic linkage of the two states in 1385/86 and the baptism of the Lithuanians into the Latin (Roman Catholic) church. The spread of Catholicism among the Lithuanians and the attendant diffusion of the Polish language, culture, and notions of political and social order among the Lithuanian nobility eroded the position of the Orthodox Ruthenians, as had happened earlier in Galicia. In 1569, by the Union of Lublin, the dynastic link between Poland and Lithuania was transformed into a constitutional union of the two states as the Polish-Lithuanian Commonwealth. At the same time, the greater part of the Ukrainian territories was detached from Lithuania and annexed directly to Poland. This act hastened the differentiation of Ukrainians and Belarusians (the latter of whom remained within the grand duchy) and, by eliminating the political frontier between them, promoted the closer integration of Galicia and the eastern Ukrainian lands. For the next century, virtually all ethnically Ukrainian lands experienced in common the direct impact of Polish political and cultural predominance.