Wikipedia
Anna-Euphrosyne Angelina or Anna-Helena Angelina (?-1253), Grand Princess consort of the Rus', was the daughter of Byzantine Emperor Isaac II Angelos and Irene Palaiologina, a daughter of George Palaiologos (according to the Russian historian Aleksandr Mayorov). In the Galician–Volhynian Chronicle she is known simply as the Grand Prince of Roman. According to Aleksandr Mayorov the first have the chronicle (Daniel of Galicia chronicle) is similar to Byzantine rather than Ruthenian historiography not out of coincidence. In his lection Mayorov tries to prove that not only the chronicle, but the prince himself has Byzantine origin.
Anna-Helena was married to the Grand Prince of Galicia and Volhynia Roman the Great in 1199-1205.
The name of Roman's wife is under discussion. The name was assumed to be Anna based on the fact that her grandchild Mstislav Danilovich established the Church of Saint Joachim and Anna in Volodymyr-Volynsky. According to the Supraśl Orthodox Monastery and Kiev Caves Monastery obituaries, her second name was Helena. It is possible that she was a daughter of Margaret of Hungary ( House of Árpád) rather than Irene Palaiologina.
In 1219 she became a nun after her older son Daniel of Galicia married the daughter of Mstislav the Bold. According to Leonid Makhnovets the widow of Roman the Great was at the burial of her grandchild Volodymyr Vasylkovich in 1288 in Liuboml, so it is possible that she died soon thereafter.
It is known that Roman the Great was killed at the Battle of Zawichost in 1205 possibly rushing to help Philip of Swabia who was married to Anna's sister Irene Angelina. The existence of relations between Philip and Roman could be traced with the fact that Roman was recorded to be among the founders of the 12th century Peterskirche of Benedictine monastery in Erfurt when he gave as a charity 20 grzywna of silver.