religious community established in the late 14th century by Geert Groote (Groote, Geert) (q.v.) at Deventer, in the Netherlands. Groote formed the brethren from among his friends and disciples, including Florentius Radewyns (Radewyns, Florentius) (q.v.), at whose house they lived. After Groote's death, Radewyns and several others became Augustinian Canons and established the Congregation of Windesheim. These two communities became the principal exponents of devotio moderna (q.v.), a school and trend of spirituality stressing meditation and the inner life and criticizing the highly speculative spirituality of the 13th and 14th centuries.

The brethren spread throughout the Netherlands, Germany, and Switzerland. They were self-supporting and lived a simple Christian life in common, with an absence of ritual. Among their chief aims were the education of a Christian elite and the promotion of the reading of devout literature. They produced finely written manuscripts and, later, printed books. They kept large schools in which the scholarship (but not the Humanistic spirit) of the Italian Renaissance was found. As a boy Erasmus was deeply influenced by them.

Groote also founded at Deventer the first house of Sisters of the Common Life. They were devoted to education, the copying of books, and weaving.

The entire devotio moderna movement was seriously affected by the religious upheaval during the Protestant Reformation, and the brethren ceased to exist early in the 17th century.