The brothers Maimonides

The brothers Maimonides

New book shines light on the relationship between law, business, and family

It’s always Moshe Maimonides who gets all the attention. But what about his little brother, David?

David was a merchant; it’s possible that his international jewel business, run on behalf of his family, is what supported Moshe after they escaped from Spain and during their first years in Cairo.

Tragically, David died in 1170, in a shipwreck on his way to India.

This saga had an impact on Jewish law, Dr. Mark R. Cohen argues. Dr. Cohen, professor emeritus at Princeton, is an expert on the Cairo Geniza. That’s the hoard of a thousand years worth of old books, letters, and contracts that provides a unique window on Jewish life in the Middle Ages. Among its treasures are letters between the Maimonides brothers.

His most recent book, “Maimonides and the Merchants,” zooms in on the legal rulings of Moses Maimonides, as he is known in English — or Rambam, which is short for Rav Moshe ben Maimon, his Hebrew name — and in particular on how he modified talmudic commercial law to account for the way international business worked in the twelfth century.

Dr. Cohen will talk about his book at the Jewish Theological Seminary in Manhattan next month. (See below.)

“Maimonides and the Merchants” grew out of Dr. Cohen’s work on an earlier book, “Poverty and Charity in the Jewish Community of Medieval Egypt.” That book used the Geniza documents to show “how poverty expressed itself in the Jewish community, and how charity was organized,” Dr. Cohen said.

Which led him to the Mishneh Torah, the legal code written by the community’s best-known rabbi, Moses Maimonides. Passages about charity in the Mishneh Torah had puzzled commentators, who couldn’t figure out how Maimonides derived his rulings from talmudic precedent. It turned out, Dr. Cohen discovered, that rather than reflecting the Talmud, those passages reflected the reality of how the Cairo Jewish community handled charity.

That opened up an interesting avenue of exploration. “I thought it would be interesting to examine Maimonides’ statements regarding other legal categories in comparison with what we know about Jewish life through the Geniza,” he said.

Dr. Cohen focused on commercial law, “since we know so much about Jewish commerce as a result of the Geniza documents.” “Maimonides and the Merchants” brings many examples of how Maimonides innovated in his rulings to reflect his time and place.

Economic life had changed for the Jews since the Talmud was composed. The earlier Babylonian Jews dealt with only local or regional markets. Cairo was a hub for international trade. Jews like the Maimonides brothers made their living buying and selling goods imported from great distances.

“Jews were deeply involved in the India trade,” Dr. Cohen said. “Jews traveled by ship across the Indian Ocean. They traded mostly on the western shores of India. After a certain period, they went back to Egypt and sold their wares, or they sent their wares with agents.”

Of course, sometimes there were problems. The agent might have failed to deliver the merchandise in time, or the goods might have been lost at sea, or they might have turned out to be worthless when they reached Cairo.

Whose fault was that? Who was responsible for the loss?

This is the stuff of commercial law. Beginning in the eighth century, Islamic jurists started figuring out how to adjudicate these disputes, and to categorize the relationship between investors and their agents.

The Talmud deals with commercial law regulating disputes between business partners. The agents, however, “differ from partners in that they’re not co-investors with the enterprise,” Dr. Cohen said. Instead, in Maimonides’ time, “the agent would do favors for the investors, who then reciprocated these favors at another time.

“Maimonides and his predecessors needed to find a way to incorporate this into the halacha, so Jews wouldn’t go to Muslim courts to arrange their agency relations.”

Letter from David Maimonides to his brother Moses, explaining that he is disregarding instructions and going to India. (Cambridge University Library)

When a dispute arose between a Jew and a Muslim, it had to be decided in the Muslim shariah court — which would send a Jewish litigant to the synagogue if he was required to take an oath. In a dispute between two Jews, the rabbinic court had jurisdiction — if the litigants agreed to it.

In the Mishneh Torah, Maimonides railed against Jews who went to the gentile courts. But railing alone couldn’t keep them away. If the rabbis couldn’t figure out how to deal with the new agency relations, the merchants would go to the court that would.

Dr. Cohen devotes a chapter of his book to a discussion of agency. Some questions that courts had to decide: Did the agent make a good-faith effort to follow instructions? Was the loss unavoidable? Or was the loss the result of the agent’s nefarious negligence?

The Talmud provided that in certain cases, such questions could be answered not by a detailed forensic investigation, but by having the responsible party take an oath attesting to his good faith efforts to do his job properly. Those cases, however, did not include a commercial agent.

Enter the Rambam, who ruled that the agents could be compelled to take an oath asserting their innocence. “He, in effect, incorporated a custom of the Muslim and Jewish merchants into a larger talmudic scheme,” Dr. Cohen wrote.

Practically, this meant that Jewish merchants didn’t have to resort to a Muslim court to extract an oath from their agents.

Problem solved.

Dr. Cohen speculates that this type of agency arrangement was something that Moses Maimonides knew firsthand.

“We have to consider the possibility that Maimonides engaged in … agency in his own merchant life — with his brother, David,” Dr. Cohen wrote. “If so, he must consistently have played the role of stationary investor, with his brother acting as agent, running the family business of importing precious gems from India. This arrangement would explain how Maimonides could have made a living and still had time for his scholarship.”

A letter from Moses about his brother, David Maimonides

The greatest misfortune that has befallen me during my entire life — worse than anything else — was the demise of the saint, may his memory be blessed, who drowned in the Indian sea, carrying much money belonging to me, him, and to others, and left with me a little daughter and a widow. On the day I received that terrible news I fell ill and remained in bed for about a year, suffering from a sore boil, fever, and depression, and was almost given up. About eight years have passed, but I am still mourning and unable to accept consolation. And how should I console myself? He grew up on my knees, he was my brother, he was my student.

 — From “Letters of Medieval Jewish Traders,” edited and translated by S. D. Goiten

Who: Dr. Mark R. Cohen

What: Book discussion, “Maimonides and the Merchants: Jewish Law and Society in the Medieval Muslim World”

When: Monday, December 4, 7:30 p.m.

Where: The Jewish Theological Seminary, 3080 Broadway, Manhattan

How much: Admission is free, but reservations are required at

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