died in 1205
In 1199 Prince Roman of Wolynia united the two territories into a powerful principality, which dominated Kijow(Kiev). He successfully battled the Poles, Lithuanians, Hungarians, and Cumans and was sought as an ally by Byzantine. Roman's son Daniel (reigned 1221–64) reunited Wolynia with Galicia in 1238 built cities (e.g.., Lwow) and encouraged a flourishing east-west trade through his lands, and fostered the development of fine arts. In 1260, however, Wolynia and Galicia were devastated by a Mongol invasion and forced to recognize the Mongol khan as their overlord.
In the course of the 14th century Wolynia was absorbed by the Lithuanian
state and Galicia by Poland. After the Polish-Lithuanian union of
1569, Wolynia was ceded to Poland. It remained a Polish territory until the
second partition of Poland (1793) transferred most of it to Russia. After World
War I it was divided between Russia and Poland and after World War II the
entire region became part of the Ukrainian S.S.R.
Daniel Of Galicia, who became one of the most powerful princes in East-Central Europe.
Son of Prince Roman, Daniel was only four years old when his father who had united Galicia and Wolynia, died in a battle against the Poles (1205). It was not until 1221 did Daniel begin to overthrow other pretenders to Roman's succession and assert his authority over Wolynia; and only in 1238 did he finally gain control of Galicia. He then directed his efforts toward enriching his domain, encouraging migrants to settle there, building cities, including Lwow( Lvov) and Chelm, and promoting the development of a flourishing trade through his lands.
After the Mongol invasions (1240–41), Daniel was compelled to recognize the Khan's suzerainty. Despite his acknowledged allegiance to the Khan, he developed close relations with his western neighbours, hoping thus to secure allies who would support his attempt to overthrow the Mongol overlords. To further this plan, he married his sons into the ruling houses of Hungary, Austria and Lithuania and promised to acknowledge the pope as head of the church in his realm.
No military aid was forthcoming, and in 1256 Daniel launched his own
campaign and drove the Mongols out of Wolynia. But in 1260
another Mongol force entered Wolynia and forced Daniel to destroy the
fortifications he had constructed in his major cities. The invaders withdrew but
asserted the permanency of their authority by leaving administrative agents to
collect taxes and recruit soldiers. Daniel, giving up plans of resistance, lived
the rest of his life as an obedient, if a reluctant, vassal of the khan.