1 This was probably the church now known as Sant Ambrogio, at Milan, where St. Ambrose and his brother, together with SS. Gervasius and Protasius, now rest. Of course the church has been rebuilt, though in ancient times. The church of SS. Nabor and Felix is that now called San Francisco.
3 [Urna.] But it would seem, though all ms. authority supports this reading, as though una, "a woman," must be the true one. For from the context it would seem plain that one of those brought in was thrown prostrate, and there is no connection in which an "urn" could be brought into the narrative. See Fleury, XVIII. 47.
18 3 This would seem to refer to the persecution stirred up by Justina, in order to gain one of the churches for Arian use. The following sentence: "Tales ego ambio defensores," was inscribed by St. Charles Borromeo on a banner of SS. Gervasius and Protasius, which he caused to be made and carried in procession through Milan at the time of the great plague.
23 The truth of this miracle, of which, unless it took place, St. Ambrose could not have spoken in a public address, is also supported by St. Augustine, who was at this time in Milan, and if not himself on the spot, as he may well have been, would at least know whether such an event had taken place. See St. Augustine, De Civ. Dei. XXII. 8, and specially, Sermo in natali Martyrum Gervasii et Protasii.
8 A Canon  of the Council of Elvira, a.d. 305 or 6, lays down that if any one is killed for breaking idols, he is not to be reckoned as a martyr, but perhaps St. Ambrose here considers the burning of the synagogue as a retaliation for the destruction of churches.