Alonso de Espina

Alonso de Espina (c. 1410 – after 1464) was a Spanish Franciscan Catholic preacher and writer. He was the author of Fortalitium Fidei, a treatise on arguments to be used to oppose detractors of Catholicism.

Thought by many to be a convert from Judaism, Alonso de Espina was for many years superior of the House of Studies of the Friars Minor at Salamanca, Spain. Recent scholarship suggests that Alonso was not a converted Jew (converso).

He was a man of great learning and attained considerable renown as a preacher, but his chief claim to fame was being the author of Fortalitium Fidei. The Fortalitium was written in 1458, but it was added to by Alonso at different times up to the year 1464. The edition published at Nuremberg in 1485 begins thus:

The fact that the Fortalitium appeared anonymously gave rise to some difference of opinion as to its authorship. However, most modern scholars attribute it to Alfonso de Spina. The Fortalitium Fidei is a treatise on various types of arguments to be used by preachers and others to oppose detractors of Catholicism. It is divided into five books: the first directed against those who deny the divinity of Jesus; the second against "heretics"; the third against the Jews; the fourth, against Muslims; the fifth gives instructions on the battle against the devil. In this last book Alonso dwells at length upon the demons and their hatred of men; the powers they have over men and the diminution of these powers, owing to the victory of Christ on the Cross, the final condition of the demons, and so on.