Petrus Alphonsi



Petrus Alphonsi (also spelled Alfonsi, Peter; born Moses Sepharadi) (1062 – 1110) was a Jewish Spanish writer and astronomer, and polemicist, who converted to Christianity. He was physician to King Alfonso VI of Castile.

Alphonsi was born at Huesca, Aragon, in 1062, and died at the age of forty-eight. He embraced Christianity and was baptized at Huesca on St. Peter's Day, June 29, 1106, in his forty-fifth year. In honor of the saint and of his royal patron and godfather he took the name of Petrus Alfonsi (Alfonso's Peter).

Alphonsi wrote about his conversion in Dialogus contra iudaeos, written in Latin. The dialogues are between Mose and Pedro (i.e. Moses Sephardi and Petrus Alfonsi, himself before and after conversion).

In England
In the Dialogus Alphonsi relates that he traveled to England as magister in liberal arts. He spent several years there. He may have been a court physician of Henry I of England. The presence of Alfonsi in the West Country in the years before that date may have contributed to the flowering of Arabic science in that region from the 1120s onwards. He discussed astronomy with Walcher of Malvern. Petrus passed on the Arabic system of astronomical graduation. They may have collaborated on a work on eclipses.

Disciplina Clericalis
Alfonsi's fame rests chiefly on a collection of thirty-three tales, composed in Latin. This work is a collection of oriental tales of moralizing character, translated from Arabic, old Persian and Hindi. It established some didactic models that would be followed by other medieval authors.

The collection enjoyed remarkable popularity, and is an interesting study in comparative literature. It is entitled Disciplina Clericalis (A Training-school for the Clergy), and was often used by clergymen in their discourses, notwithstanding the questionable moral tone of some of the stories. The work is important as throwing light on the migration of fables, and is almost indispensable to the student of medieval folk-lore. Translations of it into French, Spanish, German, and English are extant. Joseph Jacobs discovered some of the stories at the end of Caxton's translation of the fables of Æsop, where thirteen apologues of "Alfonce" are taken in fact from the Disciplina Clericalis.

An outline of the tales, by Douce, is prefixed to Ellis' "Early English Metrical Romances." Nearly all the stories are adopted in the Gesta Romanorum. Chapters ii and iii were done into Hebrew and issued under the title, Book of Enoch,. An early French translation of this Hebrew language extract was made prior to 1698 by Piques, and August Pichard published another version in Paris, 1838.

Friedrich Wilhelm Valentin Schmidt produced a scholarly edition in 1827.

Controversial writings
Like many converts of his time, Alphonsi sought to show his zeal for the new faith by attacking Judaism and defending the truths of the Christian faith. He composed a series of twelve dialogues against the Jews, the supposed disputants being Mose and Pedro (= Moses Sephardi and Petrus Alfonsi, or, in other words, himself before and after conversion). The work is praised by Raymund Martin, in his Pugio Fidei, and others, but it is little known today. Steinschneider observed that it merited the oblivion into which it has fallen, while Gröber termed it "the most important literary apologia for Christian, as opposed to Jewish, beliefs ever written," and Manitius praised the "distinguished repose of its oriental powers of reasoning and persuasion." The Dialogi in quibus impiæ Judæorum ... opiniones ... confutantur, appeared at Cologne in 1536 and later in "Biblioteca Patrum". Other books are ascribed to him, and he is sometimes confounded with Petrus Hispanus of the thirteenth century. See Steinschneider, who regards him as the probable translator of the Canones Tabularum from the Arabic. It is ascribed to one Petrus Anfulsus, who is very likely identical with Alfonsi.

Another controversial tract, described as a dialogue "Inter Petrum Christianum et Moysem Hæreticum", is said to have been written by Petrus Alphonsi. In Cambridge University, England, there is a manuscript of the fifteenth century bearing the title: "De Conversione Petri Alfonsi Quondam Judæi et Libro Ejus in Judæos et Saracenos," which is mentioned in Steinschneider's "Polemische und Apologetische Literatur," 1877, p. 224.

Other works

 * De dracone, in which he calculates movements of the stars
 * De Astronomia, contains an astronomical grid according to the Arab, Persian and Latin calendars. With them and the aid of an astrolabe it was possible to find out, with accuracy, the ascending positions of the sun, moon, and the five known planets.
 * Carta a los peripatéticos franceses.