Governor of the southern Italian province of Campania, St. Paulinus gave up his privileged position in the Roman Empire to devote himself to a life of prayer along with his wife Therasia. During this time Paulinus began to converse with several bishops, such as St. Jerome and St. Augustine. He became familiar with Augustine through correspondence with St. Alypius, who was a lifelong friend of Augustine and bishop at Thagaste.
It was through this correspondence that Paulinus wanted to learn more about Alypius and asked Alypius to write some autobiographical information.
What happened next would forever impact Western civilization.
Alypius, not wanting to write about his own life, forwarded the request to his friend Augustine, who knew him very well. Augustine in turn wrote a letter to Paulinus describing the chain of events and how he intended to fulfill the request.
[W]hen [Alypius] had read your request, desiring him to write for you a sketch of his history ... I, seeing him unable to decide between the respective claims of love and humility, transferred the burden from his shoulders to my own ... I shall therefore, with God's help, soon place in your heart Alypius just as he is.
As Alypius was a lifelong friend, Augustine's own experience and conversion were interwoven with Alypius' story, resulting in something beyond expectation. Paulinus wrote back after reading Augustine's writings and felt much closer to him than before.
[B]y the kindness of the venerable bishops Aurelius and Alypius, we came to know you through your writings against the Manichæans, love for you has taken such a place in us, that we seemed not so much to be acquiring a new friendship as reviving an old affection.
So what began as a biography of St. Alypius soon "grew legs" and expanded into Augustine's own Confessions.
It appears that the world owes a debt of gratitude to St. Paulinus, who didn't realize that in asking Alypius for a sketch of his own history, he would receive in return one of the first -- and still among the greatest -- autobiographical works ever written.
