This basilica was erected at Milan by its great fourth-century bishop, St. Ambrose, and was consecrated in the year 386. The basilica in its present form was constructed at four different periods, three of which fall within the ninth, the fourth in the twelfth, century. Yet, although the original church has disappeared, a fairly good idea of its appearance in the time of its founder may be obtained from references in the writings of St. Ambrose, supplemented by modern researches. The original edifice, like the great churches of Rome of the same epoch, belonged to the basilica type; it consisted of a central nave lighted from the clerestory, two side aisles, an apse, and an atrium. Investigations made in 1864 have established the fact that the nave and the aisles of the existing basilica correspond with those of the primitive church; the atrium, however, which dates from the ninth century, and two smaller apses, flanking a new central apse of greater depth than the original, were erected. The altar occupies about the same place as in the time of St. Ambrose, and the columns of the ciborium appear never to have been disturbed; they still rest on the original pavement. The Ambrosian basilica, so called even during the life of its founder, was consecrated under circumstances which recall one of the most momentous episodes in the relations of Church and State in the fourth century. On the death of the Emperor Gratian (383), the Empress Justina, in the name of her son, the young Valentinian II, succeeded to the government of the Western half of the Empire. Justina was a zealous Arian, and Milan, where she took up her residence, was militantly orthodox. As the Arians at the time had no place of worship in Milan, the Empress demanded one from Ambrose; but the Bishop without a moment's hesitation refused to comply with her wish. For more than a year Justina and her advisors endeavoured to attain their object; but the firmness of Ambrose, who was supported by the Catholics of Milan, brought all their exertions to naught. The crisis in the unprecedented contest came during the Holy Week of 386. Ambrose received an order to depart from the city; he replied that he would not desert his flock unless forced to do so. He then proceeded to officiate as usual at the Holy Week services in the new basilica. While these functions progressed, the basilica was surrounded by troops, with the design of seizing the Bishop and the church at one stroke, but the people refused to yield. The doors were closed, and for several days St. Ambrose and the congregation endured a siege. The soldiers, however, were by no means hostile, and many of them joined in the singing of the hymns composed by the Bishop for the occasion. Under these circumstances, practically abandoned by the soldiers as well as by the people, the Empress was forced to yield, and peace was restored. For the story of the exclusion of Theodosius from taking part in the celebration of the liturgy, as well as the submission of the great Emperor, see AMBROSE, SAINT.

After the final victory of Ambrose over the Arian faction at court, the people requested him to consecrate the basilica, which at its opening had only been dedicated. The Bishop replied that he would do so, could he obtain relics of martyrs. This obstacle was removed, St. Augustine informs us (Confess., IX, vii), by the discovery in the Naborian basilica of the relics of Sts. Gervasius and Protasius, the location of whose tombs was revealed to St. Ambrose in a vision. The translation of these martyrs' relics to the new basilica was made with the greatest solemnity, and served as the crowning triumph of the orthodox over the Arians. In the explorations of 1864 the sarcophagi which in the fourth century contained these relics, as well as the sarcophagus of St. Ambrose, were discovered in the confession of the basilica. The remains of all three saints were found in a porphyry sarcophagus to which they had been transferred, probably in the ninth century, by Archbishop Angilbert II (824-859). Like his contemporary and friend, St. Paulinus of Nola, St. Ambrose adorned the walls of his basilica with frescoes representing various scenes from the Old and New Testament. From the distich inscriptions, composed by St. Ambrose, accompanying each group, we learn what subjects were depicted. Noe, the ark, and the dove recalled a favorite subject of the catacombs, though the symbolic meaning was somewhat different. Abraham was represented contemplating the stars, less numerous than his posterity were destined to be; the same patriarch with Sara, in another scene, was acting as host to Angels. Isaac and Rebecca, two scenes from the life of Jacob, and two from that of Joseph formed part of the cycle from the Old Testament. The New Testament was represented by five scenes: the Annunciation, the conversion of Zaccheus, the Haemorrhoissa, the Transfiguration, and St. John, reclining on the breast of Our Saviour. The altar of the basilica, erected in the first half of the ninth century, is a work of rare merit. The famous brazen serpent stands on a column in the nave, on the left, and is balanced by a cross on the right. This was brought from Constantinople about the year 1001, by Archbishop Arnolf, and placed in the Ambrosian basilica under the supposition that it was the brazen serpent erected in the desert by Moses. Archaeologists regard it as very probably a pagan emblem of Esculapius.

MAURICE M. HASSETT