6 From that day, the use of the Spiritual Exercises if not under the same name and in the modern manner, at least in substance, "became familiar among the primitive Chirstians," as St. Francis of Sales taught, and as appears from clear indications in the writings of the holy Fathers. For it is thus St. Jerome exhorts the noble lady Celantia "Choose to thyself a suitable place, remote from the noise of the household, whither thou mayst betake thyself as a haven. Let there be there so much care in divine readings, such frequent turns of prayers, such steadfast thought of things to come, that thou mayest redeem the occupations of other hours by this vacation. We do not say this to withdraw thee from thine own: nay, rather we say it that thou mayst learn there and meditate how thou shouldst show thyself to thine own: nay, rather we say it that thou mayst learn there and meditate how thou shouldst show thyself to thine own." And St. Peter Chrysologus Bishop of Ravenna, in the same age as St. Jerome urges the faithful with this famous invitation: "We have given a year to the body, let us give days to the soul...Let us live to God a little who have lived the whole time to the world. Let the divine voice sound in our ears: let not the noise of the household confuse our hearing...Being thus armed brethren and thus instructed let us declare war on sins...secure of victory." But as time went on men were still held by the desire of placid solitude wherein away from witnesses the soul might give attention; nay more, it is found that in the most turbulent ages of human society men athirst for justice and truth were the more vehemently urged by the Divine Spirit seek the solitude "in order being free from bodily desire they might more often be intent on the divine wisdom in the court of the mind where all the tumult of earthly cares being silent, they may rejoice in holy mediations and eternal delights." Now after God in his supreme providence had raised up many men in his Church, abundantly endowed with supernal gifts an conspicuous as masters of the supernatural life who set forth wise rules, approved ascetical methods, whether from divine revelation, or from their own practice, or from the experience of former times; by the disposition of Divine Providence like manner, the Spiritual Exercises, properly so called were given to the world by the work of the illustrious servant of God St. Ignatius of Loyola - "a treasure," as is called by that venerable man of the Order of St. Benedict, Louis of Blois, whose opinion is cited by St. Alphonsus Liguori in a very beautiful letter "On making the Exercises in solitude" - "A treasure which God has set open for his Church in these last ages, and for which abundant thanksgiving should be rendered to Him."
Source: Mens Nostra (Vatican.va)