St. John Cassian (or St. Cassian, as he is sometimes called) was born around 360 in Marseille. Having heard of the great desert monks in the Middle East, John and a friend, Germain, traveled to Bethlehem to join a monastery and learn the ascetic life. There, stories of the great monks of the Egyptian desert led the two young friends to travel on to Egypt for a yet more intense experience of prayer, fasting, and self-denial. Eventually, John and Germain went to Constantinople, where the Patriarch, St. John Chrysostom, ordained John Cassian to the diaconate. After serving there for several years, St. John Cassian was eventually ordained priest in Rome and returned to his homeland, filled with the experiences of monastic struggle and the teachings of many great fathers (both in the desert and in the city).
Cassian brought all of these experiences back with him to Gaul where he founded the monastery of St. Victor in the forest outside Marseille. The monastic life had been introduced into Gaul by St. Martin of Tours around 360, with a translation of St. Athanasius’ Life of St. Antony as the guide and inspiration for the first monks. As the number of monasteries and the number of men entering them grew, however, the need for more ordered lessons or instructions for monks became obvious. St. John Cassian wrote two works which could be used by monasteries for this purpose: his Institutes (describing the dress, work, services, and other external aspects of monastic life) and the Conferences (which gave more in-depth insight into the spiritual struggles of monastic life and the teachings of the Egyptian fathers). St. John emphasized the importance of physical labor for monks (quoting an Egyptian saying: “A laboring monk is tempted by one demon, while a lazy one is attacked by a numberless multitude of demons.”). He described eight primary vices which the monk must struggle against: gluttony, fornication, love of money, anger, sorrow, despondency, vainglory, and pride.
The fourth century was a time of theological definition, as the nuances of Christian belief were being articulated. The persecution of Christians had ended and the Church, through the decisions of the Councils and in the writings and teachings of her leaders, was formulating doctrine and drawing the lines between orthodoxy and heresy. One of the major questions of the day was the place of grace and free will in man’s salvation.
St. John Cassian’s writings describe a cooperation between God’s grace and man’s freedom which the Orthodox Church calls synergism, as opposed to Pelagius’ heretical emphasis on man’s initiation of his own salvation, which was condemned at the third Ecumenical Council in Ephesus. Cassian wrote against the Nestorian denial of Mary as the Mother of God, which was also condemned at this Council.
St. John Cassian died in 435 (at the age of seventy-five) and his relics were buried at his monastery. His contributions to Western monasticism continued as St. Benedict, 100 years later, made use of his monastic instructions in formulating the Rule which became the standard monastic guide to this day.