In the absence of substantial historical and literary records, an overview of Judaism in the western territories of the Roman empire from the first to the fifth century necessarily relies on epigraphic and archaeological documentation. The limits imposed by the fragmentary state of the material evidence, however, and the random circumstances of its preservation, frustrate any attempt – or temptation – to paint a detailed picture of a reality that must have been internally varied and not always in step with the evolution of rabbinic Judaism in Palestine and Mesopotamia.

From the formative period of the Jewish communities in the West down to the third and fourth centuries, when the Jewish population of Italy and the Iberian Peninsula became a significant component of local society, the western branch of ancient Judaism developed far away from its homeland. Furthermore, Jewish communities in the West were under continuous pressure from a politically and culturally hegemonic environment that rejected, at least in principle, any innovation regarded as barbaric or, in any case, alien. Not surprisingly, Judaism in the West maintained a degree of independence from Palestinian Judaism, with which it began to conform – although the trend was not uniform – only from the fifth century onward and mainly in reaction to the growing success of Christianity.