CASTELLINO da CASTELLI (dei CASTELLI). — Priest and apostle of religious instruction, son of Francesco and Elisabetta de' Merli, born at Menaggio (diocese of Como), perhaps in 1476. Together with several laymen, in 1536 he founded the first school of Christian doctrine in the oratory of SS. Filippo and Giacomo in Milan, under the title Compagnia della reformatione in carità. At first he encountered opposition from the Milanese diocesan authority, without whose authorization the work had been established; but in 1540 it was approved by the vicar general and enriched with an indulgence. In a short time new schools were opened in the « Porte » of Milan, so that in 1564, when Ormaneto arrived, sent by St. Carlo as vicar general, there were already 15, and within two years their number rose to 30. They spread widely throughout northern Italy: in 1541 to Genoa, Vigevano, Verona, and Piacenza; in 1542 to Mantua and Parma; in 1545 to Lodi; in 1547 to Cremona; in 1550 to Varese; in 1551 to Novara, at the request of the bishop; in 1554 to Bergamo and Brescia; in 1560 to Rome; in 1562 to Monza, Asti, and Ascoli; and in 1565 to Como. The Compagnia also brought assistance and perfection to the schools of doctrine in Venice, Savona, Ferrara, and Turin, where it found the support of Duke Carlo Emanuele I of Savoy. In 1546 it was approved by the Council of Trent, and Pope Paul III enriched it with a seven-year indulgence.
Since the title of the Compagnia aroused suspicions, as though it recalled certain undertakings of the Innovators, in 1546 it was changed to Compagnia dei servi de' puttini in carità, that is, of those « che insegnano la festa gratis per amore di Dio a' putti e putte la vita cristiana ». From as early as 1539 it had an organization with a general prior and twelve councillors, who, in addition to teaching Christian doctrine, were required every second Sunday of the month to approach the « solita Comunione universale ».
There is debate concerning the catechism adopted by the Compagnia: whether it was the one commissioned by St. Girolamo Miani, the Dominican Tommaso da Reginaldo, or another composed by C. Probably he used an Interrogatorio del maestro al discipulo per istruire li fanciulli e quelli che non sanno nella via di Dio etc., subsequently amended by St. Carlo, to whom it was later attributed. It follows the interrogative method.
A very important figure in the movement—still little studied—of Catholic reform, begun before the Council of Trent, he was a precursor of St. Carlo, whose fame eclipsed that of C. He died on 21 September 1566 with the « consolazione di vedere - scrive il Castiglione - pienamente adempiuta la predizione da lui fatta tanti anni indietro intorno alla fine spuntata per diradare le tenebre della cristiana educazione mercè la venuta di s. Carlo a Milano ».