The Treaty of 944 between Kievan prince Igor and the Byzantine Empire has the names of many Rus' ambassadors - one of which was Jatviag Gunarev. It is also the first written documentation of the term Jatviag, or Yatviag.
When his father died in 1170, Roman the Great was bequeathed the Principality of Vladimir-in-Volhynia. He subdued the Yatvingians, and harnessed the captives instead of oxen to drag the plows on his estates.
In 1264, the Duke of Krakow, Boleslaw V the Chaste organized an expedition against Yotvingia. On 23 June 1264 the two armies met near Brańsk. The Battle of Brańsk lasted two days pitting the forces of Yotvingia, led by Komata (Kumata) against the well equipped Krakovian army. The Yotvingian forces were routed in a bloody battle and Komata was killed.