MA'ARUFYA (Aram. מַעֲרוּפְיָא), medieval Hebrew concept signifying the tie between a Christian client and the Jew who was his permanent supplier, moneylender, or financial administrator. The din ha-ma'arufya ("law of ma'arufya") was never generally prevalent; where it applied it specified that the relationship between the Jewish merchant and his client was the exclusive prerogative of that Jew alone, which the *community (kehillah) protected by means of the *ḥerem (ban). According to some scholars the term derives from the French while others consider that it comes from Arabic. Some scholars have drawn a distinction between the implications of ma'arufya and ma'arifa, considering that the first denotes a non-Jewish customer who maintains commercial relations with a certain Jew while the second denotes the exclusive right to trade with him. However, this view is untenable since both forms are used indiscriminately.
Ma'arufya was known in the communities of France and Germany in the tenth century. It is possible that this usage originated in the privileges granted to merchants by the municipal councils or lords of various European towns during the 10th and 11th centuries guaranteeing them trading monopolies. From the responsa of *Gershom b. Judah (Me'or ha-Golah), it appears that the din ha-ma'arufya was applied in almost every community. However, 11th-century sources indicate that by then the custom was not accepted everywhere: "there are places where the ma'arufya is enforced and there are places where it is not enforced" (Joseph Bonfils (Tuv Elem) in: Haggahot Maimoniyyot of Meir ha-Kohen, Hilkhot Shekhenim, 6:8). As Jewish business activities were narrowed down to *moneylending in Ashkenazi areas toward the end of the 12th century, ma'arufya lost much of its former importance. The din ha-ma'arufya is not explicitly recorded in the communities of Spain, although in them too the trend against competition is evident. The essence of ma'arufya, and often the term itself, was operative in the communities of Poland-Lithuania and Russia until the modern era. Because of the variety of occupations there, the scope of the concept was applied to give craftsmen and artisans exclusive rights over their customers. The regulations of the crafts' associations included articles intended to assure the established rights of artisans to their clients. If a craftsman had done work for the ma'arufya of another craftsman, he was obliged to remit all his profits to him without deducting his own expenses. These rights were bequeathed from father to son, and when there were no heirs the rights were transferred to the dead man's guild.
I. Levitats, Jewish Community in Russia (1943), 235ff.; Sh. Eidelberg, in: hj, 15 (1953), 59–66; Baron, Social2, 4 (1957), 185; Dinur, Golah, 1 pt. 1 (19582), 382; 2 pt. 2 (19662), 250ff.; I. Agus, Urban Civilization in Pre-Crusade Europe, 2 vols. (1965), index.