This paper focuses on the worship of the Mother Goddess in the Greek colonies on the west coast of the Black Sea from the Archaic to the Roman period. The epigraphic and the archaeological evidence demonstrate the importance of the Milesian colonies in the spread of the cult. The political aspect of the Goddess’s personality is prominent and reminds of her Phrygian position. A Great Goddess very similar to the Phrygian Matar was worshiped in Thrace and on the western shores of the Black Sea before the arrival of the Greeks in 7th century BC. The Greek colonists and the Thracians were able to recognize simultaneously the continuum and the distinction in the forms and characteristics of their respective Great Goddess.