Orthodox Remembrance Day: 19 September
Name means: the army of the Germanic god Ingwio (Old High – Russian)
Grand Duke of Kiev and Chernigov, martyr
* July 1, 1100 (?) in Kiev in Ukraine
† 19 September 1147
Igor was Grand Duke of Kiev and Chernigov/Chernihiv, he was forced to abdicate during an uprising. He then retired to a monastery with the monk’s name Gabriel. He ascended the throne of Kiev in 1146. When the inhabitants of Kiev declared Isyaslav, prince of Pereslav, Grand Duke, Igor became a monk. In 1147, the rebels tore him out of the church and killed him. In 1150, his relics were brought from Kiev to Chernigov and laid down in the Church of the Transfiguration of Christ.
Joachim Schäfer: Article Igor von Kiew, from the Ecumenical Dictionary of Saints: https://www.heiligenlexikon.de/BiographienI/Igor_von_Kiew.htm