GUICCIARDINI, PIERO. — Reformer, descendant of Francesco Guicciardini, born in Florence on 21 July 1808 and died there on 23 March 1886. In his youth he was close to the group of Tuscan liberal Catholics, acquired considerable knowledge of agricultural technology, and also devoted himself to organizing nursery schools in Tuscany, with vigilant attention to the theories and practical implementations of his time (Aporti, Naville, etc.). He separated from the Catholic Church (1836) as a result of an inner crisis, also influenced by his friendship with a group of Evangelicals (especially the Genevan Matilde Calandrini); without officially joining any Protestant sect, he began attending the services of Florence’s Reformed Evangelical church. By 1846 he was already an enthusiastic organizer.
Because of his activities opposed to the “state religion,” he was imprisoned in 1851. His confinement was later commuted to exile, and he stayed in England as a guest of the local upper aristocracy. It was during this stay that G. joined the recently established sect of the Plymouth Brethren, or Darbyites; he subsequently attracted to it Teodoro Pietricola Rossetti (cousin of the better-known Gabriele Rossetti), who later played such an important role in the Darbyite mission in Italy. In 1854 G. was rebaptized into the Darbyite sect. That same year he returned to Italy and chose Nice, in the Sardinian States, rather than Florence as his residence. He then began systematically, together with some fellow believers, the work of “evangelization” in Italy, alternating his stays in Italy with periods in England and Switzerland. He returned to Florence in 1859 after the crisis of the grand-ducal government, but later left it, disappointed by the lack of the unlimited religious freedom that he had hoped Ricasoli would make possible. He continued to supervise his evangelization effort intensely, while not joining parallel Protestant initiatives or the formulation of a common creed. In the controversy provoked by Pietricola Rossetti’s pamphlet, Principi della Chiesa romana, della Chiesa protestante e della Chiesa cristiana, published in 1865, G. declared his solidarity with Pietricola, which brought upon him the wrath of the other sects. He spent the final years of his life on his estates in Tuscany. In 1885, that is, the year before his death, because of doctrinal and disciplinary disagreements, G. separated from the Plymouth Brethren community in Florence. Of limited theological education, G. based his theories on a mixture of Protestant reform and Catholicism, namely: the Trinity, the Church as the Mystical Body of Christ, free salvation, justification by faith, anti-papalism, revivalism, and pietism.