Associations and guilds were small, unofficial groups (ranging from about 10-100 members) that met together regularly for a variety of intertwined social, religious and burial purposes. These groups were widespread in the Roman empire, especially in regions like Asia Minor, and they went by a variety of ancient terms including koinon (“association”), synedrion (“sanhedrin”), thiasos (“cult-society”), synodos (“synod”),synergasia (“fellow-workers” or “guild”), collegium (“college”), and corpus (“body”).
They could draw their membership from numerous social settings, including connections associated with the household or family, the work-place, the neighbourhood, and the temple or shrine. There were also associations consisting of persons from a common ethnic or geographic background, like the associations of Phrygians (from Asia Minor) that existed in the city of Rome and the group of Samaritans that gathered together on the Greek island of Delos.
Included among these various types of associations were the many groups of initiates that devoted themselves to “the mysteries” of specific deities, which you can read about here, including Demeter and Kore (see photo of Demeter below), Dionysos, Isis, Mithras, the Great Mother, and theGreat Gods of Samothrace. But virtually all kinds of associations chose a deity as patron of the group, honouring the gods in a variety of ways.
On this web-site you can learn about these associations and guilds in various places...