From Dom Guéranger's The Liturgical Year.
The fourth Æcumenical Council was held at Chalcedon in the church of St. Euphemia; beside the tomb of this holy virgin, the impious Eutyches was condemned, and the twofold nature of the God-Man was vindicated. The‘great martyr’ seems to have shown a predilection for the study of sacred doctrine: the faculty of theology in Paris chose her for its special patroness, and the ancient Sorbonne treasured with singular veneration a notable portion of her blessed relics. Let us recommend ourselves to her prayers, and to those of the holy widow Lucy and the noble Geminian, whom the Church associates with her.
Prayer
Præsta, Domine, precibus nostris cum exsultatione proventum: ut sanctorum martyrum Euphemiæ, Luciæ et Geminiani, quorum diem passionis annua devotione recolimus, etiam fidei constantiam subsequamur. Per Dominum.
Grant, O Lord, a joyful issue to our prayers, that we may imitate the constancy in faith of the holy martyrs Euphemia, Lucy, and Geminian, the day of whose sufferings we commemorate with annual devotion. Through.