From Dom Guéranger's The Liturgical Year:
Let us honour the group of martyrs which forms the rearguard of our triumphant Queen. Timothy, who came from Antioch to Rome, Hippolytus, Bishop of Porto, and Symphorian, the glory of Autun, suffered for God at different periods and at different places; but they gathered their palms on the same day of the year, and the same heaven is now their abode. ' My son, my son,' said his valiant mother to Symphorian, 'remember life eternal; look up, and see Him who reigns in heaven; they are not taking thy life away, but changing it into a better.' Let us admire these heroes of our faith; and let us learn to walk like them, though by less painful paths, in the footsteps of our Lord, and so to rejoice Mary.
Prayer
Auxilium tuum nobis, Domine, quæsumus, placatus impende: et intercedentibus beatis martyribus tuis Timotheo, Hippolyto et Symphoriano, dexteram super nos tuæ propitiationis extende. Per Dominum.
We beseech Thee, O Lord, to be appeased, and to impart to us Thy help: and, by the intercession of blessed Timothy, Hippolytus, and Symphorian, Thy martyrs, extend over us the right hand of Thy mercy. Through our Lord, etc.