Even if it did not quite "save civilization", Ireland was one of the monastic centers of Europe in the early middle ages. In fact the Church in Ireland was dominated by monasteries and by monastic leaders. Other Irish monks became missionaries and converted much of Northern Europe. St. Columba (521 -597) and his followers converted Scotland and much of northern England. Columba did not leave a written rule. But the following rule, attributed to him, was set down much later. It does reflects the spirit of early Irish Monasticism.
Be alone in a separate place near a chief city, if thy conscience is not prepared to be in common with the crowd.
Be always naked in imitation of Christ and the Evangelists.
Whatsoever little or much thou possessest of anything, whether clothing, or food, or drink, let it be at the command of the senior and at his disposal, for it is not befitting a religious to have any distinction of property with his own free brother.
Let a fast place, with one door, enclose thee.
A few religious men to converse with thee of God and his Testament; to visit thee on days of solemnity; to strengthen thee in the Testaments of God, and the narratives of the Scriptures.
A person too who would talk with thee in idle words, or of the world; or who murmurs at what he cannot remedy or prevent, but who would distress thee more should he be a tattler between friends and foes, thou shalt not admit him to thee, but at once give him thy benediction should he deserve it.
Let thy servant be a discreet, religious, not tale-telling man, who is to attend continually on thee, with moderate labour of course, but always ready.
Yield submission to every rule that is of devotion.
A mind prepared for red martyrdom [that is death for the faith].
A mind fortified and steadfast for white martyrdom. [that is ascetic practices] Forgiveness from the heart of every one.
Constant prayers for those who trouble thee.
Fervour in singing the office for the dead, as if every faithful dead was a particular friend of thine.
Hymns for souls to be sung standing.
Let thy vigils be constant from eve to eve, under the direction of another person.
Three labours in the day, viz., prayers, work, and reading.
The work to be divided into three parts, viz., thine own work, and the work of thy place, as regards its real wants; secondly, thy share of the brethen's [work]; lastly, to help the neighbours, viz., by instruction or writing, or sewing garments, or whatever labour they may be in want of, ut Dominus ait, "Non apparebis ante Me vacuus [as the Lord says, "You shall not appear before me empty."].
Everything in its proper order; Nemo enim coronabitur nisi qui legitime certaverit. [For no one is crowned except he who has striven lawfully.]
Follow alms-giving before all things.
Take not of food till thou art hungry.
Sleep not till thou feelest desire.
Speak not except on business.
Every increase which comes to thee in lawful meals, or in wearing apparel, give it for pity to the brethren that want it, or to the poor in like manner.
The love of God with all thy heart and all thy strength;
The love of thy neighbour as thyself
Abide in the Testament of God throughout all times.
Thy measure of prayer shall be until thy tears come;
Or thy measure of work of labour till thy tears come;
Or thy measure of thy work of labour, or of thy genuflexions, until thy perspiration often comes, if thy tears are not free.
From A. W. Haddan and W. Stubbs, Councils and Ecclesiastical Documents Relating to Great Britain and Ireland II, i (Oxford: Oxford University Press, 1873), pp. 119-121.