Reina was born about 1520 in Montemolín in the Province of Badajoz. From his youth on he studied the Bible. In 1557 he became a monk of the Hieronymite Monastery of St. Isidore of the Fields, outside Seville (Monasterio Jerónimo de San Isidoro del Campo de Sevilla). At this time he had contact with Lutheranism and he became an adherent of the Protestant Reformation. He fled with about a dozen other monks when they came under suspicion by the Office of the Inquisition for Protestant tendencies. He first turned to John Calvin's Geneva but he did not find the atmosphere of doctrinaire rigidity of the Calvinist Church to be welcoming. In 1558, Reina declared that Geneva had become "a new Rome" and left.
In exile on the Continent
In Seville, (in April 1562), the Inquisition made an auto-da-fé in which an image of Casiodoro was burned. The works of Reina and his colleagues were placed in the Index of prohibited books and he was declared a "heresiarch" (leader of heretics).
Reina wrote the first great book against the Inquisition: "Sanctae Inquisitionis hispanicae artes aliquot detectae, ac palam traductae" (Some arts of Holy Inquisition). This work was printed in 1567 in Heidelberg under the pseudonym: Reginaldus Gonsalvius Montanus.
He secretly translated the work of the critic of Calvin, Sebastian Castellion, De haereticis, an sint persequendi (Concerning Heretics, Whether They Should Be Persecuted), that condemns executions "for reasons of conscience" and documents the original Christian rejection of this practice.
While in exile, variously in London, Antwerp, Frankfurt, Orléans and Bergerac, funded by various sources (such as Juan Pérez de Pineda) Reina began translating the Bible into Spanish, using a number of works as source texts. For the Old Testament, the work appears to have made extensive use of the Ferrara Bible in Ladino with comparisons to the Masoretic Text and the Vetus Latina. The New Testament derives from the Textus Receptus of Erasmus, with comparisons to the Vetus Latina and Syriac manuscripts. For the New Testament he had great aid from the translations of Francisco de Enzinas and Juan Pérez de Pineda.
It is speculated that Reina's Bible, published in Switzerland in 1569, which became the basis of the Reina-Valera Bible, was a composite work of the expatriate Isidorean community, done by several different hands with Reina first among them.
Reina was granted citizenship by the city of Frankfurt on 16 August 1571. During this period he worked as a silk trader, to get the money for his family. Step by step he became a true member of the Lutherans. About 1580 he published a Catechism, in the sense of Luther's Catechism, in Latin, French and Dutch.
- Confessión de Fe cristiana (hecha por ciertos fieles españoles, los cuales, huyendo los abusos de la Iglesia Romana y la crueldad de la Inquisición de España, dexaron su patria, para ser recibidos de la Iglesia de los fieles, por hermanos en Christ). London, ca. 1560 - Reprint: Confessión de fe Christiana. The Spanish Protestant Confession of Faith. Exeter, 1988, edited by A. Gordon Kinder
- Sanctae Inquisitionis hispanicae artes aliquot detectae, ac palam traductae. Heidelberg, 1567, under the pseudonym: Reginaldus Gonsalvius Montanus; the Spanish title: Algunas artes de la Santa Inquisición española; (in English: Some arts of Holy Inquisition)
- La Biblia que e los Sacros libros del Vieio y Nuevo Testamento ... Transladada en Espanol. Basel, 1569
- Evangelium Ioannis. Frankfurt am Main, 1573; published in Latin; in the Spanish title: Comentarios a los Evangelios de Juan y Mateo
- Expositio primae partis capitis quarti Matthaei. Frankfurt am Main, 1573; Dutch translation by Florentius de Bruin, Dordrecht, 1690; published in Latin; in the Spanish title: Comentarios a los Evangelios de Juan y Mateo
- Sixtus Senensis, ed.: Bibliotheca sancta à F. Sixto Senensi ex praecipuis catholicae ecclesiae authoribus collecta. Frankfurt am Main, 1575
- Confessio in articulo de coena. Antwerpen, 1579
- Catechismus, Hoc est: Brevis instructio de praecipuis capitibus christianae doctrinae, per quaestiones & responsiones, pro Ecclesia Antwerpiensi quae Confessionem Augustanam profitetur. Antwerpen, ca. 1580; published in Latin, French and Dutch; the Spanish title: Catecismo
- Estatutos para la sociedad de ayuda a los pobres y perseguidos, in Frankfurt.
- Exposión de la primera parte del capitulo cuarto de San Mateo sobre las tentaciones de Cristo, edited by Carlos López Lozano. Madrid, 1988
- scientifically proven - compare: Reina. In: Allgemeine Deutsche Biographie (ADB). Band 27, Duncker & Humblot, Leipzig 1888, S. 720–723. (in German)
- Hermann Dechent: Reina. In: Allgemeine Deutsche Biographie (ADB). Band 27, Duncker & Humblot, Leipzig 1888, S. 720–723. (in German)
- Balderas, Eduardo. "How the Scriptures Came to Be Translated into Spanish", Ensign, September 1972.
- Erich Wenneker (1994). "REINA, Cassiodoro di". In Bautz, Traugott. Biographisch-Bibliographisches Kirchenlexikon (BBKL) (in German) 7. Herzberg: Bautz. cols. 1524–1528. ISBN 3-88309-048-4.
- compare: Hermann Dechent: Reina. In: Allgemeine Deutsche Biographie (ADB). Band 27, Duncker & Humblot, Leipzig 1888, S. 720–723. (in German)
- Inquiries with the: Karlsruher Virtuellen Katalog
- Kinder, A. Gordon. 1975: Casiodoro de Reina: Spanish Reformer of the Sixteenth Century. Tamesis, London. ISBN 0-7293-0010-2
- Wenneker, Erich (1994). "REINA, Cassiodoro di". In Bautz, Traugott. Biographisch-Bibliographisches Kirchenlexikon (BBKL) (in German) 7. Herzberg: Bautz. cols. 1524–1528. ISBN 3-88309-048-4.
- Dechent, Hermann (1888), "Reina", Allgemeine Deutsche Biographie (ADB) (in German) 27, Leipzig: Duncker & Humblot, pp. 720–723
- Herero, José: Bible Translation History: Spanish Bible
- Rosales, Raymond S. Casiodoro de Reina, patriarca del Protestantismo hispano, in Serie de monografías [de las] Publicaciones del Seminario Concordia, no. 5. Saint Louis, Mo.: Concordia Seminary Publications, 2002. ISBN 0-911770-74-7
- Biography of Casiodoro de Reina in the Center for Reformation Studies (Spanish)
- Biography of Casiodoro de Reina from the Servetus International Society (Spanish)
- Works by Casiodoro de Reina at Project Gutenberg
- Works by or about Casiodoro de Reina at Internet Archive