1 St Ambrose, 340-397 (Pastoral Doctor)
St Ambrose is the first Doctor of the Church and called the Pastoral Doctor. He placed the church first with each member as his highest priority. Service to each member and defending that honor was his daily and continual aim throughout his lifetime.
Ambrose is also called the "Patron of the Veneration of Mary". He firmly maintained that population increases in direct proportion to the esteem virginity is held. He laid the foundation for Marian thinking in the West.
Nearly everyone knows that it was due to St Monica's prayers and St Ambrose's support that Monica's son found God and was bapized by Ambrose. That person later became a bishop for many years in Africa and later a great pastor himself, and a Doctor of the Church. He is Saint Augustine.
St Ambrose started his career as a young politican and became the people's choice to become Bishop of Milan when the Arian bishop died. He had great presence and was one of the most influential men of the fourth century. His great speaking ability, tact, and decisiveness brought the emperor to do penance for crimes committed.
"It was but natural that a prelate so high-minded, so affable, so kind to the poor, so completely devoting his great gifts to the service of Christ and of humanity, should soon win the enthusiastic love of his people. Rarely, if ever, has a Christian bishop been so universally popular, in the best sense of that much abused term, as Ambrose of Milan. This popularity, conjoined with his intrepidity, was the secret of his success in routing enthroned iniquity." The quote is taken from New Advent listed in the resources at the end, below.