| Honorific Prefix: | Saint |
| Juan de Castillo | |
| Honorific Suffix: | S.J. |
| Birth Date: | 14 September 1595 |
| Birth Place: | Belmonte, Cuenca |
| Beatified Date: | 28 January 1934 |
| Canonized Date: | 16 May 1988 |
| Canonized By: | John Paul II |
| Major Shrine: | Caibaté |
| Feast Day: | 17 November[1] |
| Attributes: | Martyr-saint |
Juan de Castillo (14 September 1595 – 17 November 1628) was a Jesuit priest and missionary, and a martyr-saint of the Catholic Church. A Spaniard, he was one of the first to labor at the Jesuit reductions in Paraguay.
Born on 14 September 1596 in Belmonte, in the region of Toledo in Spain, Juan del Castillo began studies for the legal profession at the University of Alcalá, but discovered, at the beginning of his career, a very different goal.[2] He entered the Society of Jesus on 21 March 1614 in the novitiate in Madrid, in preparation for becoming a Jesuit priest.[3]
In November 1616 he was sent with Alphonsus Rodriguez to South America.[4] They arrived in Buenos Aires on February 15, 1617[5] and he went to Cordoba to continue his studies. He was ordained a priest in 1625.
The Jesuits arrived at Asuncion in 1588[6] and created the Jesuit reductions of Paraguay among the native Guaranis in 1609.[7] At that time the Jesuit province of Paraguay did not correspond to the current borders. It included the current Paraguay, Uruguay, Argentina, a small part of Bolivia, and Brazil.[8] Their purpose was to protect the natives from the Portuguese settlers, which quickly brought on hostility from these settlers.
Juan del Castillo began his missionary work immediately after being ordained a priest. He joined at Ijuí Roque González y de Santa Cruz who left him at the head of this reduction and went to found a new one. At Ijuí, presently in the western Brazilian municipality of Rio Grande do Sul, Juan helped Christianize the Guaranis, and taught the youngest to read and write.
Juan del Castillo was assassinated on 17 November 1628 in Yjuhi,[9] two days after his companions Roque Gonzalez and Alphonsus Rodriguez. The chieftain Nheçu, head of the surrounding region, was hostile to their Christianizing efforts. He ordered his men to murder the three religious, and he condemned all missionaries in general.[10] Juan was murdered in the forest, but brought back and buried with his companions in the reduction of the Immaculate Conception.[11]
Juan del Castillo along with Roque Gonzalez de Santa Cruz and Alfonso Rodriguez were beatified by Pope Pius XI in 1934. They were then together canonized on 16 May 1988 by John Paul II. The following is an excerpt from the homily of John Paul II during the canonization Mass in Asuncion (Paraguay):