The mother of St Augustine, Monica, was married to a pagen named Patricus. She had a hard life, her husband was regularly unfaithful to her, as recorded by her son in his "Confessions." Monica had a wonderful gift of bringing peace to a broken friendship, she had the gift of reconciliation.
There is a beautiful story about Monica. She was sitting on the shores of Hippo, a city in North Africa, watching her son go off to Rome, then a city of evil, and she cried bitter tears for the sake of her son. The Bishop of Hippo was with her and he said that God could never refuse such tears from a mother.
Later, after her son's conversion, Monica lived with him in Milan. From there she went to Rome and saw that the Romans did things differently during church services than they did in Milan. She wrote to St. Ambrose, bishop of Milan at the time, and asked him what she should do. Ambrose replied, "When in Rome do what the Romans do." This is where this famous saying comes from.
Monica died in her son's arms at age 56.