The principality of Galicia-Volhynia to the southwest has highly developed trade relations with its Polish, Hungarian, and Lithuanian neighbors and emerges as another successor to Kievan Rus'.

In the early thirteenth century, Prince Roman Mstislavich had united the two previously separate principalities, conquered Kiev, and assumed the title of grand duke of Kievan Rus'.

His son, Prince Daniil (Danylo; r. 1238-64), is the first ruler of Kievan Rus' to accept a crown from the Roman papacy, apparently doing so without breaking with Orthodoxy.

Early in the fourteenth century, the patriarch of the Orthodox Church in Constantinople grants the rulers of Galicia-Volhynia a metropolitan to compensate for the move of the Kievan metropolitan to Vladimir.

However, a long and unsuccessful struggle against the Mongols combine with internal opposition to the prince and foreign intervention to weaken Galicia-Volhynia.

With the end of the Mstislavich Dynasty in the mid-fourteenth century, Galicia-Volhynia cease to exist; Lithuania takes Volhynia, and Poland annexes Galicia.