First century synagogues in their Greco-Roman context
By the time of Jesus there were synagogues wherever there were communities of Jews in the [Roman] empire, both in Palestine and abroad. In many respects these were not unlike the gathering places of like-minded individuals among non-Jews, where certain religious activities occurred and prayers were said. Greco-Roman “associations” were commonly organized, for example, for workers of the same trade in a locale, who might share a range of common interests. And it was not unusual to find other associations organized for the purpose of periodic social gatherings, where members would pool their funds to provide ample food and drink and, perhaps strangely to the modern observer, provide, through a reserve, a proper burial for their deceased members.
Rarely, though, would such organizations, whether trade associations or funeral clubs, include men, women, and children; rarely would they meet together every week; and rarely would they devote themselves principally to the purpose of prayer and discussion of sacred traditions. To this extent, Jewish synagogues were distinctive. (Bart D. Ehrman, The New Testament: A Historical Introduction to the Early Christian Writings, Oxford: Oxford University Press, 2000 , 37-38)