St. Agnes, a Roman maiden, in her thirteenth year was beheaded, in the year 304, for the sole reason that she was a Christian. The original Mass for her feast in the Gregorian Sacramentary had a magnificent Preface not inserted in modern Missals. She is praised by all the Fathers of the Latin Church; the family of Constantine built a magnificent basilica at her tomb.
(Source: Fr. Lasance, The New Roman Missal)