The law of inheritance, the concentration of a family’s wealth in property, and the division of that property into small fields made it likely that even after the death of their father brothers would be involved in each other’s lives. Imagine a family of two brothers and a sister. The parents would give some of their wealth, particularly in movable property (e.g., textiles, jewelry, cash) but also perhaps including some land, to their daughter around the time of her wedding. When the father dies, the two brothers inherit the estate, although their father’s wife (who may or may not be their mother) has a lien on the estate for the amount of her prestipulated marital settlement. According to the biblical laws of inheritance, the first born son receives a double-portion – in this case, that would mean two-thirds of the estate (after deducting what was owed to their father’s wife) goes to the oldest son and one-third to the youngest. In such a case, it would be more probable that the estate could be divided “cleanly”, with some fields given outright to the youngest son who might then move to a new household.
Such a “clean” division, however was not always easy. The composition of the holdings (e. g., unevenly sized or productive fields), the number of brothers (the more brothers the more equitable their inheritance settlement), or the availability and cost of dwellings (should one brother inherit thelr father’s dwelling, the others might not be able to find suitable housing in range of their landholdings) might all complicate such an arrangement. Moreover, I have found no evidence that the law of first-born inheritance was actually practiced.
For better or worse, then, brothers were often stuck with each other. Their joint ownership of a family dwelling might have limited their mobility often keeping them in close proximity sometimes even in the same house. One mishnah discusses the case of brothers living together and sharing some, but not all, property and clothing. Another mishnah imagines brothers living in individual apartments within a single courtyard. A papyrus scrap, probably of a census or tax document, suggests that this was not an uncommon occurrence. Familiarity with one’s brother is assumed: According to one rabbinic source, a man is expected to know his brother’s handwriting, just as he knows the signature of his father and teacher.
Whether or not they lived together, however, many more brothers found themselves in joint business ventures. Here, the documentary record is relatively strong. several papyri use the conventional phrase “the inheritors of so-and-so” to indicate ownership of a field. A “document of deposit” in Greek from 110 CE appears to deal with a case in which two brothers were in business with each other and one of them died, leaving his share of the business to his son. Rather than liquidate the property and clear the debt, the remaining brother wrote a kind of I.O.U. to his nephew. Papyri explicitly mention brothers owning fields jointly.
Rabbinic sources, too, support the idea that brothers often found themselves jointly owning business property. One source discusses the possibility of brothers dividing a field that they presumably inherited together into individually held plots only to reunite them; most likely they would be more profitable that way. Rabbinic law dealing with the payment of second and poor tithes favors partnerships, explicitly mentioning property jointly owned by brothers. In some agricultural cases, brothers are in fact assumed to be acting in partnership. Special rules that govern brothers serving as witnesses reflect the assumption that they share interests.
Michael Satlow, “What Does Love Have to Do with It? Sibling Relationships among Judean Jews in the First-Third Centuries CE”, in Ehe-Familie-Gemeinde, eds. Dorothee Dettinger and Christof Landmesser (Leipzig: Evangelische Verlangsanstalt, 2014), 108-110.