Franciscan priest. Baptized Paul Jerome Casanova in his native town of Porto Maurizio (Liguria), he was educated by the Jesuits in Rome, but joined the Franciscan Order as a young man. He completed his studies at St Bonaventure's College on the Palatine and was ordained priest in 1703. In 1709 he restored the Florentine friary of San Francesco del Monte to a state of austere fidelity to Francis's teaching on poverty. Soon its denizens increased in numbers and they preached with success throughout Tuscany. Soon Leonard became Guardian and established a mountain hermitage at Incontro, where the friars retired twice a year to live in solitude, fasting, and silence like primitive monks.
In 1730 he was appointed Guardian at St Bonaventure's, Rome: for six years he preached to soldiers, sailors, convicts, and galley-slaves as well as giving parish missions. From 1736 he preached in Umbria, Genoa, and the Marches of Ancona, often in the open air as the churches were too small. Frequently he preached the Way of the Cross and set up about 500 sets of Stations of the Cross in Italy. This devotion is still popular today.
In 1744 he was sent to Corsica in the hope that his energetic preaching would restore peace and order there. The problems he faced were feuds, vendettas, lawlessness, ignorance, and neglect of religion. Some men came to his sermons fully armed. Unfortunately he was regarded as an emissary of Genoa, whose government sent a ship to rescue him after six months. Even the pope recognized that it was inadvisable for him to return.
In 1750, a Jubilee year, he set up Stations of the Cross in the Colosseum. After preaching extensively in Lucca the following year, his strength failed and he died at Rome.
Writer as well as preacher, he composed numerous devotional treatises and letters: his most famous work is his Resolutions. Cardinal Henry of York helped to further his cause: Leonard had been his mother's spiritual director. He was beatified in 1796 and canonized in 1867. He is patron of popular missionaries. Feast: 26 November.
Works ed. by B. Innocenti (1915); Lives by L. de Cherance (1903), G. Cantini (1936), and F. M. Pecheco (1963). See also B.L.S., xi. 208–9; Bibl. SS., vii. 1208–21.