Saint John Cassian (ca. 360 – 435) (Latin: Jo(h)annes Eremita Cassianus, Joannus Cassianus, or Joannes Massiliensis), John the Ascetic, or John Cassian the Roman, was a Christian theologian celebrated in both the Western and Eastern Churches for his mystical writings. He is known both as one of the "Scythian monks" and as one of the "Desert Fathers."

John Cassian was born around 360, likely in the region of Scythia Minor (now Dobruja in modern-day Romania and Bulgaria), although some scholars assume a Gallic origin.

As a young adult he and an older friend, Germanus, traveled to Palestine, where they entered a hermitage near Bethlehem. After remaining in that community for about three years, they journeyed to the desert of Scete in Egypt, which was rent by Christian struggles. There they visited a number of monastic foundations.

Approximately fifteen years later, in c.399, Cassian and Germanus fled the Anthropomorphic controversy provoked by Theophilus, Archbishop of Alexandria, with about 300 other Origenist monks. John Cassian and Germanus went to Constantinople, where they appealed to the Patriarch of Constantinople, Saint John Chrysostom, for protection. John Cassian was ordained a deacon and was made a member of the clergy attached to the Patriarch while the struggles with the imperial family ensued. When the Patriarch was forced into exile from Constantinople in 404, the Latin-speaking John Cassian was sent to Rome to plead his cause before Pope Innocent I.

Augustine of Canterbury (circa first third of the 6th century – probably 26 May 604) was a Benedictine monk who became the first Archbishop of Canterbury in the year 597. He is considered the "Apostle to the English" and a founder of the English Church.

Augustine was the prior of a monastery in Rome when Pope Gregory the Great chose him in 595 to lead a mission, usually known as the Gregorian mission, to Britain to Christianize the King Æthelberht of the Kingdom of Kent from his native Anglo-Saxon paganism. In a letter to the patriarch of Alexandria detailing early successes of the mission, Gregory wrote of having sent Augustine and his companions "to the ends of the earth". Kent was probably chosen because it was near the Christian kingdoms in Gaul and because Æthelberht had married a Christian princess, Bertha, daughter of Charibert I the King of Paris who was expected to exert some influence over her husband. Before reaching Kent the missionaries had considered turning back but Gregory urged them on and, in 597, Augustine landed on the Isle of Thanet and proceeded to Æthelberht's main town of Canterbury.

John Henry Newton (July 24, 1725 – December 21, 1807) was a British sailor and Anglican clergyman. Starting his career at sea, at a young age, he became involved with the slave trade for a few years. After experiencing a religious conversion, he became a minister, hymn-writer, and later a prominent supporter of the abolition of slavery. He was the author of many hymns, including "Amazing Grace" and "Glorious Things of Thee are Spoken."

John Newton was born in Wapping, London, in 1725, the son of John Newton Sr., a shipmaster in the Mediterranean service, and Elizabeth Newton (née Seatclife), a Nonconformist Christian. His mother died of tuberculosis in July, 1732, about two weeks before his seventh birthday. Two years later, he went to live in Aveley, the home of his father's new wife. Newton spent two years at boarding school. At age eleven he went to sea with his father. Newton sailed six voyages before his father retired in 1742. Newton's father made plans for him to work at a sugar plantation in Jamaica. Instead, Newton signed on with a merchant ship sailing to the Mediterranean Sea.