FRATRICELLI, in Ecclesiastical History, an enthusiastic sect of Franciscans, which rose in Italy, and particularly in the marquisate of Ancona, about the year 1294. The word is an Italian diminutive, signifying fraterculi, or little brothers; and was here used as a term of derision, as most of those who composed the body were apostate monks, whom the Italians call fratelli, or fratricelli. For this reason the term fratricelli, as a nick-name, was given to many other sects, such as the Catharists, the Waldenses, and the like, however different in their opinions or in their conduct. But this denomination, applied to the austere part of the Franciscans, was considered as honourable.

The founders were P. Mauratoand P. de Fossombroni, who obtained of Pope Celestin V. permission to live in solitude as hermits, and to observe the rule of St Francis in all its rigour. They were joined by several idle vagabond monks, who, living after their own fashion, and making all perfection to consist in poverty, were soon condemned by Pope Boniface VIII. and his successor, and the inquisitors were ordered to proceed against them as heretics. This commission was executed with the usual barbarity. They were compelled to flee into Sicily, where Peter John Oliva de Serignan had published his Comment on the Apocalypse, and they adopted his errors.

They predicted the reformation of the church, and the restoration of the true gospel of Christ, by the genuine followers of St Francis, and declared their assent to almost all the doctrines which were published under the name of the abbot Joachim, in the Introduction to the everlasting Gospel ; a book published in 1520, and explained by one of the spiritual friars of the name of Gerhard. Among other enormities inculcated in this book, it is pretended that St Francis was the angel mentioned in Rev. xiv. 6, and had promulgated to the world the true and everlasting gospel of God; that the gospel of Christ was to be abrogated in 1620, and to give place to this new and everlasting gospel, which was to be substituted in its room; and that the ministers of this great reformation were to be humble and bare-footed friars, destitute of all worldly employments. It is mentioned by some writers that they even elected a pope to be head of their church; at least they appointed a general, with superiors, built monasteries, and made other arrangements for the new faith. They were condemned anew by Pope John XXII. in consequence of whose cruelty they regarded him as the true antichrist; but several of them returning into Germany, were sheltered by Lewis duke of Bavaria, the emperor.

There are accounts bearing that no less than two thousand persons were burnt by the Inquisition from the year 1318 to the time of Innocent VI. for their inflexible attachment to the poverty of St Francis. The severities against them were again revived towards the close of the 15th century, by Pope Nicoas V. and his successors. However, all the persecutions which this sect endured were not sufficient to extirpate it; for it subsisted until the times of the reformation in Germany, when its remaining votaries adopted the cause and embraced the doctrine and discipline of Luther.