Founder of the Brethren of the Common Life, born Deventer, Holland, 1340; died 1384. He taught theology at Cologne and after spending some years in solitude and prayer in Munnikhuizen monastery was ordained a deacon and preached at Utrecht. Many disciples flocked around him, and he founded with Florence Radewiyns his institute at Zwolle. Groote, who was the first successful practical mystic, died a martyr of charity, leaving his institute to be organized into a community of canons regular by Radewiyns.