Anthony, John, and Eustathios references on wikipedia
Anthony,_John,_and_Eustathios Anthony, John, and Eustathius (Eustathios, Eustace; RussianRussian Orthodox Church. Their feast day is celebrated on April 14 in the horlogion.They were attached to the Muscovite missionaries dispatched to the court of Algirdas (Olgierd), pagan Grand Duke of Lithuania. Algirdas was married to an Orthodox Christian princess, Maria of Vitebsk, and the Orthodox were permitted only to minister to the religious needs of the princess. All outside proselytizing was forbidden.