The Brethren of the Common Life was a Roman Catholic pietist religious community founded in the Netherlands 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 to Jesus Christ. They believed that Christianity should be practiced not only in formal religious settings, but also in everyday life, and they sought to promote a practical spirituality that emphasized personal piety and devotion.

Gerard Groote, otherwise Gerrit or Gerhard Groet, in Latin Gerardus Magnus, was a Dutch Catholic deacon, who was a popular preacher and the founder of the Brethren of the Common Life. He was a key figure in the Devotio Moderna movement.