Roman the Great

Roman Mstislavich (c. 4 April 1152 – 19 June 1205), also known as Roman the Great, was Prince of Novgorod (1168–1170), Volhynia (1170–1189; 1189–1205), and Galicia (1189; 1198/99–1205). He founded the Romanovichi branch of Rurikids, which would rule Galicia–Volhynia until 1340.

By seizing the throne of Galicia, he dominated the western regions of Kievan Rus'. In the early 13th century, Byzantine chroniclers applied the imperial title of autocrate (αύτοκράτωρ) to him, but there is no evidence that he assumed it officially.

He waged two successful campaigns against the Cumans, from which he returned with many rescued captives. The effect of Roman's victory was, however, undermined by new divisions among the princes of Rus'.

Roman was killed during the Battle of Zawichost, where his forces were crushed by the Polish forces led by Leszek the White, Duke of Sandomierz, and his brother Konrad I of Masovia.

Source: Wikipedia — https://en.wikipedia.org/wiki/Roman_the_Great