The Jews were at this period the principal representatives of the commerce of the world. While the nobles devoted themselves to the business of war, the commoners to trades, and the peasants and serfs to agriculture, the Jews, who were not liable to be called upon to perform military service, and possessed no feudal lands, turned their attention to the exportation and importation of goods and slaves, so that the favor extended to them by Charlemagne was, to a certain extent, a privilege accorded to a commercial company. They experienced only the restraint put upon all merchants in the corn and wine trade; the Emperor considered it dishonest to make a profit on the necessaries of life. This somewhat materialistic value set upon the Jews marks, however, great progress from the narrow-mindedness of the Merovingian monarchs, the Gunthrams and the Dagoberts, who saw nothing in the Jews but murderers of God. But Charlemagne also manifested deep interest in the spiritual advancement of the Jewish inhabitants of his empire. In the same way as he had cared for the education of the Germans and the French by inviting learned men from Italy, so also he earnestly desired to place a higher culture within the reach of the German and the French Jews. With this intention he removed a learned family, consisting of Kalonymos, his son Moses, and his nephew, from Lucca to Mayence (787), hoping besides to make the Jews independent of the academies of the Levant. Charlemagne's embassy to the powerful Caliph Haroun Alrashid, to which was attached a Jew named Isaac, is familiar to every student of history (797). Although at first probably Isaac accompanied the two nobles, Landfried and Sigismund, only in the character of interpreter, he was nevertheless admitted into Charlemagne's diplomatic secrets. Thus, when the two principal ambassadors died on the journey, the Caliph's reply and the valuable presents which he had forwarded, fell into Isaac's sole charge, and he was received in solemn audience by the Emperor at Aix. The Emperor is also said to have requested the Caliph, through his embassy, to send him from Babylonia a learned Jew for his country, and Haroun is reported to have sent him a man answering his requirements. This man was a certain Machir, whom Charlemagne placed at the head of the Jewish congregation of Narbonne. Machir, who, like Kalonymos of Lucca, became the ancestor of a learned posterity, founded a Talmudical school at Narbonne.