What was it like to be an immigrant in the Greco-Roman world? Well, the answer given by many scholars of the past has been that it was not very good at all for immigrants. Without necessarily actually looking at any archeological or inscriptional evidence, some scholars tend to assume that foreigners were faced with significant hardships and feelings of rootlessness. Robert Turcan is somewhat representative of common views when he speaks of a “troubled and drifting world” in which “uprooted people”, particularly immigrants, lived “on the fringes of a disintegrating world” in both the Hellenistic and Roman eras (Turcan, The Cults of the Roman Empire [A. Nevill trans.; Oxford: Blackwell, 1996], 16-17).
Often this view of immigrant hardship is coupled with overstated notions regarding the decline of the ancient city in the Hellenistic and following eras, which resulted in general feelings of detachment and a lack of social connection. I have dealt with such problematic theories of decline in a full article under my publications (“The Declining Polis? Religious Rivalries in Ancient Civic Context”).
It is true that immigrants, foreigners or minorities could, at times, be faced with negative attitudes or treatment associated with xenophobia (fear of foreigners), so there were certainly negative sides to immigrant experience (see ‘Come! Plunge the knife into the baby’: Tertullian’s not-so-subtle retort). Nonetheless the all-encompassing scholarly picture of immigrants adrift in a disintegrating society does not fit with the actual evidence we have available, at least in the case of Syrian or Phoenician expatriots in the Hellenistic and Roman eras.
My recent research into inscriptions that involve Syrians who settled elsewhere and formed themselves into associations points rather to the ways in which such “foreigners” maintained connections with the cultural traditions of their homeland while also finding a home for themselves in the society of settlement. Syrian immigrants acculturated, to various degrees, to local customs while also sustaining a sense of distinctiveness. In particular, there is a consistency in Syrians’ attention to the “gods of the homeland”. I am developing these ideas further for a forthcoming publication, but you can also see an inscription or two in an earlier post: For the gods of the homeland: Immigrants from Beirut on a Greek island.
In this respect, there are significant commonalities between Syrians and Judeans (Jews) or Israelites (Samaritans) in the ways that they found a place for themselves in cities of the ancient Mediterranean world. See, for example my post ‘Tis the season . . . : Jewish and Roman holidays and my article Acculturation and Identity in the Diaspora: A Jewish Family and ‘Pagan’ Guilds at Hierapolis.
Unofficial groups in the Greco-Roman world that I (and others) typically call “associations” used a variety of terms to describe themselves. Some of the favourite Greek terms were synodos (“synod”), koinon, synergasia (“guild”), thiasos (“cult-society”), and mystai (“initiates”). Today, when people (including many scholars) hear the term synagogue or head-of-the-synagogue (archisynagogos) they tend to assume some Jewish group (or building) is in mind. However, the term synagogue (stemming from the Greek synagō, meaning to gather or bring together) was also used by other “pagan” associations and was not necessarily a sign of Jewish connections.
Thus, for instance, one monument from Apamea in Bithynia (northern Asia Minor / Turkey), which involves a group of men and women devotees (thiasitai and thiastides) honouring a priestess of Cybele (the Great Mother), mentions that the inscription was set up in the “synagogue” of Zeus (IApamBith 35). Across the Propontis in Perinthos-Herakleia in Thracia, there was an occupationally-based “synagogue of oar (or small-ware) dealers” that shows no sign of Jewish connections (IPerinthos 59 [first or second century]). At both Beroia and Hagios Mamas in Macedonia there were associations (devoted to Poseidon and a hero-god respectively) whose main leader was known as the head-of-the-synagogue (archisynagogos) (IMakedD 747 [second century]; SEG 27  267). And there are many other “pagan” cases where the chief leader of the group, as in some Jewish gatherings, was termed head-of-the-synagogue (e.g. NewDocs I 5; IG X.2 288-289; SEG 42  625).
Diaspora Jewish groups (including Jesus-devotees) shared more in common with “run-of-the-mill” associations of the Greco-Roman world than often acknowledged, and their “gatherings” would have been viewed as such by outsiders in some important respects.
To read more about associations in the Greco-Roman world, as well as their relevance to early Judaism and Christianity, go to the Associations in the Greco-Roman World site (under my websites above).
Until recently, the suggestion that members of the early Christian congregations may have simultaneously been members in other associations and guilds remained under-explored. In Associations, Synagogues, and Congregations (click the Books / Articles tab for a free download), I dealt with the question of multiple memberships in connection with the Christians at Corinth (addressed by Paul in 1 Cor 8 and 10) who were attending banquets alongside non-Christians (“pagans”). I also considered the possibility that the opponents addressed by John’s Apocalypse, especially those accused of eating idol-food (or idol-meat) with “Jezebel”, may have been encountering sacrificial food as members in the guilds of Thyatira (something that William Ramsay suggested, but did not explore, long ago).
In a more recent article dealing with Sardis and Smyrna, which you can read on my publications page, I looked at the implications of multiple memberships for questions of rivalries and competition among different groups.
I have now just read a very interesting article on associations on the island of Rhodes by Vincent Gabrielson, which drew my attention to another interesting case of multiple memberships in associations (dealing with IG XII 155). A man named Dionysodoros, who was an immigrant from Alexandria (in Egypt), was honoured by a number of associations (koina) at Rhodes in the second century BCE, including the “Haliasts and Haliads,” the “Paniasts,” and the “Dionysiasts” (devoted to the god Dionysos). A closer look at this lengthy inscription shows that he was not only honoured by these groups, but was also a member in at least four associations at Rhodes! (See Vincent Gabrielson, “The Rhodian Associations Honouring Dionysodoros from Alexandria, ” Classica et mediaevalia 45  137-60.)
And these memberships were not fleeting. Dionysodoros was a member of the “Haliasts and Haliads” for 35 years, and he acted as their chief-of-banquets (archeranistas) for 23 years. Simultaneously he was a faithful member and benefactor of other associations, including the “Paniasts” whom he served as chief-of-banquets for at least 18 years. This is the sort of atmosphere of multiple affiliations and interactions in which the early Christians and diaspora Jews found themselves. So we should not be too surprised if we find some Jews or Christians going to synagogue or church one day, and hanging out with friends in the guild or association the next.