St. Ambrose is one of the Church Fathers, a Doctor of the Church, one of the most illustrious of the saints and opponent of the heresy of Arianism. Ambrose's family was Christian, with martyrs in their ancestry. Ambrose was the youngest of three children and was educated in Rome. By 370, he was made consular general of Liguria and Aemilia, Italy, by Emperor Valentinian. His official residence was Milan.

In 374, the bishopric of Milan became vacant, and various groups met to propose a candidate. Ambrose, as consular general, had to maintain order and went to the city's basilica to talk to the people assembled. Before he could persuade the apposing factions, a voice of a small child echoed in the structure, crying: "Ambrose, Bishop." After a stunned silence, the people picked up the same cry: "Ambrose, Bishop." Ambrose was unanimously elected on the spot. This election was not as uncommon as it appears, as Ambrose was well-educated, an opponent of the Arian heresy, and a man respected by all. Emperor Valentinian supported the election, and Ambrose, at first quite unprepared to accept such an honor, acquiesced to the election. He was thirty-five years old at the time.

He began his episcopacy by giving up all his worldly goods and titles and then educating himself in the Scriptures and the writings of the Fathers of the Church. He was already an eloquent preacher, and he maintained a vigorous schedule of prayer, including night vigils. He also kept his door open to the poor and needy.

In 375, Valentinian died, and the emperor's brothers, Valens, began a joint rule with Gratian, Valentinian's son. Empress Justina, a member of the Arian heresy, put her four-year-old son on the throne of Italy, and Ambrose naturally became her enemy. Ambrose never wavered in this battle, limiting the damage the Arians could have done. In 383, Gratian was slain by a usurper, Maximus. The son of Justina, Valentinian, defeated Maximus and executed him. Valentinian opposed the Arians, and when his mother died, sided with Ambrose against Theodosius I, who ruled in the West. Theodosius' agents had murdered seven thousand citizens, a crime that roused Ambrose. He stopped Theodosius on the porch of a church and publicly scolded him for his actions. Theodosius submitted and performed public penance. Later, Theodosius commented: "I know of no bishop worth of the name, except Ambrose."

In May 393, Valentinian II was murdered in Gual while Ambrose was traveling to meet and baptize him. Another usurper, Eugenius, embraced paganism and opened the old Roman temples before Theodosius led his armies into the region and slew him. Ambrose was asked to perform the solemn rites of thanksgiving for this victory. Theodosius died the following year with Ambrose at his side. Two years later, Ambrose himself collapsed. He was on his deathbed when he received delegations of concerned officials who asked him to pray that God would spare his life for the good of the empire. Ambrose declined and died on Good Friday, April 4, 397.

Throughout his episcopal years, Ambrose was known for miracles. His writings have served the Church through the centuries, many of which are in the form of homilies or sermons. He also wrote hymns, commentaries on the Scriptures, and mystical writings. His discourse on the duties of Church officials became a standard for later generations. Ambrose is also revered because of his disputes with St. Augustine of Hippo. Augustine converted as a result of these disputes and was baptized by Ambrose.

Ambrose is buried in Milan with relics of Sts. Gervase and Protase, which he discovered. He is the patron of Milan and Bologna, as well as candle makers, beekeepers, gingerbread makers, and stone masons. One of his hymns is used to bring about good weather. St. Ambrose is declared a Doctor of the Church which are certain men and women who are revered by the Church for the special value of their writings and preaching and the sanctity of their lives. They each made important and lasting contributions to the faith and are to be recognized for their great merits.

To be declared a Doctor of the Church, you have to meet three basic requirements:

1. First, you must have lived a life of exemplary holiness, or insignis vitae sanctitas (outstanding sanctity). In short, you have to be a saint.
   

2. Second, to be a Doctor of the Church you must have deepened the whole Church's understanding of the Catholic Faith with emins doctrina (eminent teaching). Which is to say, sanctity isn't enough. There are thousands of saints, but only 37 Doctors of the Church. To be a Doctor one must do more than just live the Faith. Rather, one must significantly and profoundly contribute to our understanding of Divine Revelation, helping us to know more deeply some truth about God and His actions in the World.
   

3. And third, a pope must officially declare you a Doctor. That being said, as the Church understands it, when a pope declares someone a Doctor of the Church, he's not so much making someone a Doctor as he is recognizing what the Holy Spirit has already done - that He has conferred the charism of Doctor upon them.