The Brethren of the Common Life was a religious community founded in the 14th century by Gerard Groote, formerly a successful and worldly educator who had had a religious experience and preached a life of simple devotion. A small band of followers attached themselves to Groote and became his fellow-workers, thus becoming the first "Brethren of the Common Life". The reformer, of course, was opposed by the clergy whose evil lives he denounced, but the cry of heresy was raised in vain against one who was as zealous for purity of faith as for purity of morals. The best of the secular clergy enrolled themselves in his brotherhood, which in due course was approved by the Pope. Groote, however, did not live long enough to finish the work he had begun. He died in 1384, and was succeeded by Florence Radewyns , who two years later founded the famous monastery of Windesheim which was thenceforth the centre of the new association.

The Confraternity of the Common Life resembled in several respects the Beghard and Beguine communities which had flourished two centuries earlier and were then decadent. The members took no vows, neither asked nor received alms; their first aim was to cultivate the interior life, and they worked for their daily bread. The houses of the brothers and sisters occupied themselves exclusively with literature and education, and priests also with preaching. When Groote began, learning in the Netherlands was rare; the University of Leuven had not yet been founded, and the fame of the schools of Liège was only a memory. Apart from some of the clergy who had studied at Paris or Cologne, there were no scholars in the land; even amongst the higher clergy there were many who were ignorant of Latin, and the burgher was quite content if when his children left school they were able to read and write.

Groote determined to change all this, and his disciples accomplished much. Through their unflagging toil in the scriptorium and afterwards at the press they were able to multiply their spiritual writings and to publish them widely. Amongst them are to be found the choicest flowers of fifteenth-century Flemish prose. The Brethren spared no pains to obtain good masters, if necessary from foreign parts, for their schools, which became centres of spiritual and intellectual life; amongst those whom they trained or who were associated with them were men like Thomas à Kempis, Dierick Maertens , Gabriel Biel , and the Dutch Pope Adrian VI. Before the fifteenth century closed, the Brethren of the Common Life had placed in all Germany and the Netherlands schools in which the teaching was given for the love of God alone.

Gradually the course, at first elementary, embraced the humanities, philosophy, and theology. The religious orders looked askance at these Brethren, who were neither monks nor friars, but the Brethren found protectors in Pope Eugenius IV, Pope Pius II, and Pope Sixtus IV. The great Cardinal Nicholas of Cusa had been their pupil and became their stanch protector and benefactor. He was likewise the patron of Rudolph Agricola, who in his youth at Zwolle had studied under Thomas à Kempis; and so the Brethren of the Common Life, through Cusa and Agricola, influenced Erasmus and other adepts in the New Learning. More than half of the crowded schools -- in 1500, Deventer had over two thousand students -- were swept away in the religious troubles of the sixteenth century. Others languished until the French Revolution, while the rise of universities, the creation of diocesan seminaries, and the competition of new teaching orders gradually extinguished the schools that regarded Deventer and Windesheim as their parent establishments.