Vasylko Rostyslavych (Vasyly; ca 1066–28.02.1124) – Prince of Terebovlia (early 1090 s – 1124), the third son of the founder of the Halych princely dynasty Rostyslav Volodymyrovych of Tmutorokan and Lanka, daughter of King Béla I of Hungary.
Born probably in Tmutorokan. After the death of his father (1067) together with elder brothers was evicted from the city. The Prince-outcast served at the court of the Prince Yaropolk Iziaslavych of Volyn. J. Dlugosz states that Vasylko headed troops in the border conflict with Poland in 1081. After his elder brother Riurik became established in Peremyshl (now Przemyśl, Poland), moved to him, strengthened his positions in Halych lands and got the Terebovlia Principality. Fought actively for the retention of Halych lands by the Rostyslavychi.
During the Polish-Halych war of 1091–1092, with the assistance of the Pechenegs and Torks he inflicted several blows on the Poles. Initiated the development of the Dnister lower reaches. Took part in the battle of 1091 at the bank of the River Maritsa where Emperor Alexius I Komnenos, along with Polovtsian Khans Tugorkan and Boniak, crushed the Pecheneg army. It was after that battle that the Pechenegs disappeared gradually, instead the Polovtsians became the rulers of the steppe. In 1097 he took part in the Liubech Congress of Princes. When the Congress ended, Vasylko, foully slandered by the Prince Davyd Ihorovych of Volyn, was treacherously captured and blinded by order of Kyivan Prince Sviatopolk Iziaslavych near Kyiv (now the village of Bilohorodka, Kyiv-Sviatoshyne District, Kyiv Oblast). These events are reproduced in The Tale ofBlinding of Vasylko of Terebovlia (1097).
Blind Vasylko successfully ruled his principality under the extremely adverse circumstances. In 1099 he, together with his brother Volodar, defeated troops of Kyivan and Smolensk Princes in the battle at Rozhne Pole (west of the town of Zolochiv, Lviv region). That same year at the River Vihor, near Peremyshl, with the assistance of the Polovtsian Khan Boniak the Rostyslavychi defeated the Hungarian army headed by Prince Koloman.
Together with the Polovtsians and some Rus princes Vasylko Rostyslavych waged several campaigns against Poland. The chronicle compiled by a Peremyshl burgher in the 16 th c. tells under the year of 1089 that Prince Vasylko Rostyslavych with the Polovtsians invaded Polish lands, burnt down many castles and captured many Poles.
According to the decision of the Vytychiv Congress of 1100, Vasylko Rostyslavych was deprived of Terebovlia, but he did not submit to such decision and remained in the town. In 1118 Vasylko Rostyslavych and Volodar helped the Prince Volodymyr Monomakh of Kyiv to restrain Yaroslav Sviatopolchych; in 1122 Vasylko ransomed Volodar from the Polish captivity.
In 1123 he was an ally of Prince Yaroslav Sviatopolchych, aiding in his struggle against Andriy Volodymyrovych, son of Prince Volodymyr Monomakh, in Volodymyr. Kyivan princes had to reckon with Vasylko Rostyslavych.