This great Holy Father was born in 365 years in Dobrudja, then called Little Scythia, in a place named from ancient times to the present Cassian Plateau and Cassian's Cave . The town of Casimcea in Tulcea County also bears his name. Coming from a distinguished family, he attended the schools of his epoch. But enlivened by a burning thirst for spiritual perfection, he gives up as a young man the vain and deceptive attractions of worldly life and goes to the Holy Places (Holy Land) accompanied by his friend Herman, brother not by birth, but by spirit. This is how both of them became monks in a monastery in Bethlehem. Establishing themselves in the coenobitical tradition according to the monastic way of life of the monks of Palestine, Mesopotamia and Cappadocia, and in their desire for greater perfection, they decided to leave for the anchoretic sites of Egypt, among the solitary monks of whose holy life they heard. That's how they came to the communities in the Nile Delta, getting deeper from there in the wilderness. But everywhere they went, they searched with zeal for the solitary saints, so that they could honour the splendour of grace and the wealth of their fruits, and ask them spiritual counsels for the salvation of the soul. These questions and answers will be left to us as a holy inheritance in the Conferences of the Desert Fathers, with which St John Cassian endowed the Church.

Acquiring what they could gather from their heavenly doctrine, to Abba Joseph's advice, they remained in Egypt seven years, and then went on to take spiritual advice from these teachers in their spiritual fight from time to time, until they arrived in the notorious Skete wilderness, founded and made the bright wilderness worthy of being celebrated by all by St. Macarius. Here, a great number of monks were living in a severe asceticism, among whom were Abbas Moses, Serapion, Teona, Isaac, and Pafnutius the priest.

Seven years later, John Cassian and Herman returned to Bethlehem, where they had acquired from their spiritual father the blessing of living here from now on in a solitary way of life. And so they left with zeal and hurry for Egypt. But with all their longing, they could not regain the silence of contemplation because of unjust accusations against the monks of Egypt by Archbishop Theophilus of Alexandria. Then John Cassian and Herman, following a group of 50 monks, resolved to seek quietness in Constantinople, under the protection of St. John Chrysostom. This was happening in the 401 AD. As soon as the great patriarch saw them and the quality of their souls, he managed to persuade Herman to receive the priesthood through his hands and convinced John Cassian to become deacon. Conquered by the purity and holiness of St. John Chrysostom and his unspoiled craftsmanship, John Cassian sat down with a warm zeal under his spiritual guidance and consented to sacrifice the wilderness in order to make profit from living near such a spiritual teacher.

But it did not last long time until St. John Chrysostom, a victim of Theophilus, was taken to exile, and John Cassian and Herman were sent to Rome by the clergy and the people, accompanying Bishop Paladius to make known to the Bishop of Rome, Innocent I, in a letter, on the sufferings of St. John Chrysostom. St. John Cassian spent ten years in Rome, and during that time he was ordained a priest. From here he went to Marseilles, in southern Gaul, where he founded, for men, the Monastery of Saint Victor, on the tomb of a third-century martyr and for the women, that of the Monastery of Saviour, in the year 415 AD. As man much tried in the ascetic life, and at the same time spiritual father arrived to a great pastoral wisdom, he offered to the multitude of monks who gathered around him the true monastic tradition he had received from the Holy Fathers in the East, taking into account the living conditions in Gaul, the climate and the nature of the inhabitants here.

At the request of St. Castor, the bishop of Apt, he wrote his work Institutes of the Coenobia (the rules for monastic common life), for the monasteries he had established in Provence. In this book he describes the way of living of the monks in Egypt, but with some adaptations in what was too harsh for the monks in Gaul, following here also the monastic customs that used to be in Palestine, in Cappadocia, in Mesopotamia.

Later he completed this spiritual teaching through the Conferences of the Desert Fathers in which he depicts, at the request of the hermits who lived in Lerins and the Hâeres Islands near Marseilles, the higher stages of the spiritual fight for cleansing the heart in view of contemplation, using the teachings of the great anchorites who had met him in Egypt. St. John Cassian thus endowed, from its beginnings, monasticism in Galia with a thorough spiritual teaching, inspired the living fountains of the Desert Fathers.

As a faithful disciple of the Great Cappadocian Fathers Basil the Great, Gregory the Theologian, and Gregory of Nissa, as well as St. John Chrysostom, St. John Cassian latter on rose up against the deep separation between human nature and divine grace, promoted by Augustine, fighting against Pelagius' doctrine.

In regard of these long-standing oppositions, John Cassian remained steadfast in the true faith of the Church, and away from the noise and quarrels, he taught with the depth of divine contemplation, the mystery of an unspeakable and gentle peace and of a serene stillness. He entrusted his soul to God in peace in the year 435 AD. Known as a saint by those of his time, he is honoured by all the monks of the Western Church as their Father and one of the greatest teachers. His holy relics are preserved to this day in St. Victor's Monastery in Marseilles.

(excerpts from the Life of the Saints/ doxologia.ro)