Aetheria uses the words psalm, antiphon and hymn in connection with the musical parts of the worship she observed, but not indiscriminately. She was probably familiar with hymns as they had developed in the fourth century both in the eastern and western churches. It has been assumed that the hymn sung at the daily lighting of the candles was _Phos hilaron_, “O gladsome light.”[5] The hymns she heard at the Good Friday observance have been tentatively identified as the _Idiomela_ for Good Friday, traditional in Byzantine ritual.[6] In any case they were true hymns, perhaps of a metrical, or more probably of a rhythmical type. It is impossible to identify the processional hymns of which she speaks. All that can be asserted is that non-scriptural, as well as scriptural hymns, were sung in the processions at Jerusalem. In Constantinople, contemporary processions have already been mentioned. The practice of Jerusalem was also adopted there. In the sixth century under Justinian, the Feast of Ypapanti was introduced.[7] However, the history of Byzantine processions must be omitted from this study which is devoted primarily to the Latin West. In Rome, the Christian procession had an independent origin, being derived in part from the memorial honors paid to the Christian martyrs and in part from the Christianization of pagan ceremonies. When the period of persecution of Christianity had come to a close and the triumphant Church was able to assert publicly her influence and authority at Rome, processions were made as early as the fifth century to the places where martyrs had suffered. This is the origin of the later station procession, followed by the celebration of mass in the various churches where the remains of martyrs removed from the catacombs were buried. A century earlier in Milan, Ambrose had discovered and removed the bodies of St. Protasius and of St. Gervasius from their original burial place to a church newly erected in their honor.[8] Pope Gregory the Great (590-604) observed the Roman stations and Pope Sergius (687-701) completed their organization.[9] The processions were accompanied by the chanting of psalms but there is no record of non-scriptural hymns. The symbolism of the procession, however, was enriched by the idea of pilgrimage to a spot made sacred by martyrdom, a continuing processional motive throughout the Middle Ages.