customs had continued unchallenged by the state. Valentinian II The childless Gratian had treated his younger brother Valentinian II like a son. Ambrose, on the other hand, had incurred the lasting enmity of Valentinian II's mother, the Empress Justina, in the winter of 379 by helping to appoint a Nicene bishop in Sirmium. Not long after this, Valentinian II, his mother, and the court left Sirmium; Sirmium had come under Theodosius' control, so they went to Milan which was ruled by Gratian. In 383 Gratian was assassinated at Lyon, in Gaul (France) by Magnus Maximus. Valentinian was twelve years old, and the assassination left his mother, Justina, in a position of something akin to a regent. In 385 (or 386) the emperor Valentinian II and his mother Justina, along with a considerable number of clergy, the laity, and the military, professed Arianism. Conflict between Ambrose and Justina soon followed. The Arians demanded that Valentinian allocate to them two churches in Milan: one in the city (the Basilica of the Apostles), the other in the suburbs (St Victor's). Ambrose refused to surrender the churches. He answered by saying that "What belongs to God, is outside the emperor's power." In this, Ambrose called on an ancient Roman principle: a temple set apart to a god became the property of that god. Ambrose now applied this ancient legal principle to the Christian churches, seeing the bishop, as a divine representative, as guardian of his god's property. Subsequently, while Ambrose was performing the Liturgy of the Hours in the basilica, the prefect of the city came to persuade him to give it up to the Arians. Ambrose again refused. Certain deans (officers of the court) were sent to take possession of the basilica by hanging upon it imperial escutcheons. Instead, soldiers from the ranks the emperor had placed around the basilica began pouring into the church, assuring Ambrose of their fidelity. The escutcheons outside the church were removed, and legend says the children tore them to shreds. Ambrose refused to surrender the basilica, and sent sharp answers back to his emperor: "If you demand my person, I am ready to submit: carry me to prison or to death, I will not resist; but I will never betray the church of Christ. I will not call upon the people to succour me; I will die at the foot of the altar rather than desert it.