The angry empress then renewed her attack more fiercely.  She commanded the troops to seize by force one of the churches of the city for the use of the Arians; and the bishop was celebrating the sacred mysteries on Palm Sunday when news was brought to him of this outrage,—­of this encroachment on the episcopal authority.  The whole city was thrown into confusion.  Every man armed himself; some siding with the empress, and others with the bishop.  The magistrates were in despair, since they could not maintain law and order.  They appealed to Ambrose to yield for the sake of peace and public order.  To whom he replied, in substance, “What is that to me?  My kingdom is not of this world.  I will not interfere in civil matters.  The responsibility of maintaining order in the streets does not rest on me, but on you.  See you to that.  It is only by prayer that I am strong.”

Again the furious empress—­baffled, not conquered—­ordered the soldiers to seize the person of Ambrose in his church.  But they were terror-stricken.  Seize the minister at the altar of Omnipotence!  It was not to be thought of.  They refused to obey.  They sent word to the imperial palace that they would only take possession of the church on the sole condition that the emperor (who was controlled by his mother) should abandon Arianism.  How angry must have been the Court!  Soldiers not only disobedient, but audaciously dictating in matters of religion!  But this treason on the part of the defenders of the throne was a very serious matter.  The Court now became alarmed in its turn.  And this alarm was increased when the officers of the palace sided with the bishop.  “I perceive,” said the crestfallen and defeated monarch, and in words of bitterness, “that I am only the shadow of an emperor, to whom you dare dictate my religious belief.”

Valentinian was at last aroused to a sense of his danger.  He might be dragged from his throne and assassinated.  He saw that his throne was undermined by a priest, who used only these simple words, “It is my duty to obey God rather than man.”  A rebellious mob, an indignant court, a superstitious soldiery, and angry factions compelled him to recall his guards.  It was a great triumph for the archbishop.  Face to face he had defeated the emperor.  The temporal power had yielded to the spiritual.  Six hundred years before Henry IV. stooped to beg the favor and forgiveness of Hildebrand, at the fortress of Canossa, the State had conceded the supremacy of the Church in the person of the fearless Ambrose.

Not only was Ambrose an intrepid champion of the Church and the orthodox faith, but he was often sent, in critical crises, as an ambassador to the barbaric courts.  Such was the force and dignity of his personal character.  This is one of the first examples on record of a priest being employed by kings in the difficult art of negotiation in State matters; but it became very common in the Middle Ages for prelates and abbots to be ambassadors of princes, since they were not only the most powerful but most intelligent and learned personages of their times.  They had, moreover, the most tact and the most agreeable manners.