Although no distinctive architecture or layout distinguishes early synagogues, a deliberate attempt was made to avoid copying pagan temples. They were modeled on Greek and Roman assembly halls, with smaller halls for other functions such as legal business. This reflects the fundamental difference between a pagan temple and a synagogue. The former was considered to be the home of a deity, and the worshippers remained outside; the latter, a place for worship, study, and debate that was conducted within.

The Jewish community in the Roman Diaspora was relatively large and dates to the second century BC. Its history in ancient Rome is known from classical authors, from Talmudic texts, and from tomb inscriptions found in the Jewish catacombs. The tombstones provide information about the officials of the Jewish community and mention the names of the Roman synagogues. One of them is the Synagogue of the Subura, although no inscriptions mention it before AD 70. After the destruction of Jerusalem, the community remained removed from the new, rabbinical Judaism of Judaea, and retained several archaic characteristics.

The majority of the names on the inscriptions are Greek. There is only a small number of Roman names, and very few Hebrew or Aramaic names. This suggests that most Roman Jews were culturally Greek, not Latins. They were also rather poor and appear to have lived in a quarter near the Porta Capena. Many Jews were settled in Rome after the war against Pompey in 63 BC. (The oldest inscriptions mention freed slaves, who must have been Pompey's prisoners of war.) During the reign of Augustus, there may have been as many as 40,000 Jews living in Rome, and the number likely rose considerably after the fall of Jerusalem in AD 70.

The Synagogue of the Subura may have been founded by freedmen who had been prisoners of war after the fall of Jerusalem. They were involved in such urban renewal projects as the Colosseum and the temple of Peace during the time of Vespasian. The sole synagogue in Rome during the time of Julius Caesar was also located in the Subura.

The word "synagogue" comes from a Greek translation of the Hebrew term beit knesset, a house of assembly.

Here are a few resources for additional information about the Jewish Diaspora in ancient Rome.