Abba Mari ben Moses ben Joseph, was a Provençal rabbi, born at Lunel, near Montpellier, towards the end of the 13th century. He is also known as Yarhi from his birthplace (Hebrew Yerah, i.e. moon, lune), and he further took the name Astruc, Don Astruc or En Astruc of Lunel.
The descendant of men learned in rabbinic lore, Abba Mari devoted himself to the study of theology and philosophy, and made himself acquainted with the writings of Moses Maimonides and Nachmanides as well as with the Talmud.
In Montpellier, where he lived from 1303 to 1306, he was much distressed by the prevalence of Aristotelian rationalism, which in his opinion, through the medium of the works of Maimonides, threatened the authority of the Old Testament, obedience to the law, and the belief in miracles and revelation. He therefore, in a series of letters (afterwards collected under the title Minhat Kenaot, i.e., "Jealousy Offering") called upon the famous rabbi Solomon ben Aderet of Barcelona to come to the aid of orthodoxy. Ben Adret, with the approval of other prominent Spanish rabbis, sent a letter to the community at Montpellier proposing to forbid the study of philosophy to those who were less than twenty-five years of age, and, in spite of keen opposition from the liberal section, a decree in this sense was issued by Ben Adret in 1305. The result was a great schism among the Jews of Spain and southern France, and a new impulse was given to the study of philosophy by the unauthorized interference of the Spanish rabbis.