In 1961, Ileana entered the Orthodox Monastery of Our Lady of All Protection/ Notre Dame de Toute Protection, in Bussy-en-Othe, France. On her tonsuring as a monastic, in 1967, Sister Ileana was given the name Mother Alexandra. She moved back to the United States and founded the "Orthodox Monastery of the Transfiguration" in Ellwood City, Pennsylvania, the first English language Orthodox monastery in North America. She was the third female descendant of Queen Victoria to become a Mother Superior in a convent of her own foundation along with Princess Alice of Battenberg and Princess Elizabeth of Hesse. She served as abbess until her retirement in 1981, remaining at the monastery until her death.