FRATRICELLI was a common name given to a number of obscure mediteval sects who flourished in the 13th and 14th centuries. They were also called Bioschi, Bighini, Bocasoti, Frerots, &c., and included such sects as the Brethren of the Full Spirit, the Brethren of the Free Spirit, the Beghards, the Brethren of the Common Life, &c. The history of these medival sects is very obscure ; but it seems now made out that while they had some relation to and sympathy with the older Cathari and other Manichwan heretics, they had a distinct origin in the Franciscan order, and that their real aim was to carry out the principles of St Francis even in defiance of the court of Rome. Their origin has been traced to Peter of Macerata and Peter of Fossombrone, who put themselves at the head of certain malcontent Franciscans, who, having been condemned by Pope Celestine in 1294, declared that the rule of Francis was of more authority than any pope, and that papal opposition only showed that the pope himself might become anti-Christian. They soon began to teach opposition to the pope, the clergy, and the church. They held millenarian views, and preached and practised communism after the fashion, they said, of the early Christians. Their opinion soon spread among the Franciscan Tertiaries, and the common people everywhere favoured them. Boniface VIII. ordered the Inquisition to look after them, and on a report of Matthew of Chieti they were condemned in 1297 and handed over to the Inquisition. This only roused opposition. They held a general meeting in Rome, elected a pope of their own, organized themselves, spread over Europe, and by preaching missions made converts everywhere. Their ranks were continually recruited from the malcontent friars, especially from the Franciscans. Pope John XXII. condemned them under the names of Fratricelli, Fratres de paupera vita, Bizochi, and Bighini, and issued briefs against them in 1322 and 1331. They gave great trouble to the church in Strasburg, Cologne, and the Rhineland. In Italy their headquarters were in the Mark of Ancona and in Turin, where persecutions were organized against them in 1335, 1368, 1373-88. Popes Martin V., Eugenius IV., and Nicholas V. also persecuted them. In spite of all they survived until the Reformation. Their smouldering fire probably burnt itself out in the Anabaptist movement of the 16th century.

The best collective accounts are to be found in Moshchn, De Beguinis et BeguinaInts, and Hahn's Gesch. der Ketzer Mittel-alter, vol. ii. bk. iv.