structural:reformatting, linguistic:paraphrasing
Early life and reign

Daniel's father, Roman Mstislavich, united the principalities of Galicia and Volhynia in 1199. After his death in 1205, the boyars of Galicia forced the four-year-old Daniel into exile with his mother Anna of Byzantium and brother Vasylko Romanovich. After the boyars proclaimed one of their own as prince, the Poles and Hungarians invaded the principality, ostensibly to support the claims of young Daniel and Vasylko, and divided it between themselves. In 1219, he renounced his claims to Galicia in favor of his father-in-law, Mstislav the Bold.

In 1221, Daniel re-established his rule over Volhynia, where the boyars and populace had reaffirmed their loyalty to his dynasty. In 1234, he defeated Alexander Vsevolodovich, taking the Duchy of Belz. By 1238, he had defeated former Dobrzyń Knights at Drohiczyn (Dorohochyn), and regained most of Galicia, including the capital. While the Prussians were under pressure from the Teutonic Order, Daniel attempted to conquer a related people, the Yatvingians.