Sister Callista Mares (Hedwig Mares) was born Feb. 4, 1918 in Cistern, TX to Cyril and Augusta Otahal Mares. She received her early education a St. Wenceslaus School in Cistern and finished her high school at Nazareth Academy in Victoria. She entered as a postulant May 10, 1937, Hedwig received the habit and the name Sister Callista at Blessed Sacrament Convent in San Antonio. She was professed Dec. 19, 1938. To prepare for her teaching ministry, Sister Callista obtained her degree from Incarnate Word Convent, San Antonio, majoring in history and minoring in philosophy. She was sent to various mission schools where she taught mainly on the primary, elementary and junior high levels.