Patristic citations of parts of the Roman Canon shed light on its history and theology. At the Te igitur, according to St. Leo, the church and its leaders are remembered: De fratribus vero quos et epistolis tuis et legatorum nostrorum relatione communionis nostrae cupidos esse cognovimus pacis et communionis nostrae unitate laetentur . De nominibus autem Dioscori, Juvenalis, et Eusthatii ad sacrum altare recitandis dilectionem tuam hoc decet custodire, quod nostri ibidem constituti faciendum esse dixerunt, quodque honorandae S. Flaviani memoriae non repugnet, et a gratia tua Christianae plebis animos non avertat But concerning the brothers whom we learn from your letters and from the delegates report desire to be in communion with us they may be heartened by their unity of peace and communion with us . Best foreign countries to visit However, concerning the recitation of the names of Dioscorus, Juvenal and Eustathius at the sacred altar, it behooves you, beloved, to hold to that which our brothers who were present said ought to be done and which is not incompatible with the honorable memory of St. Flavian and will not turn the souls of the laity away from you Ep. 80: PL 54, 913-915. In his letter to Justinian Ep. 4 ad Just., 2: PL 69, 22, Pope Vigilius cites the Te igitur with the words pro Ecclesia quam adunare, regere, custodire digneris You have been deemed worthy to unite, to rule, to defend on behalf of the church. The practice of naming bishops in this part of the Mass should be seen in the context of the doctrinal controversies of that time, when communion with a group of bishops assured orthodoxy of faith.