Romano-Celtic shrines, like later Celtic myths, tell of triple goddesses such as the Proximae (kinswomen), Dervonnae (oak-sprites) and Niksai (water-goddesses).
1999 — Jean Markale, The Great Goddess: Reverence of the Divine Feminine from the Paleolithic to the Present (trans. Jody Gladding), Inner Traditions International (1999; originally published in French in 1997), →ISBN, page 95:
They make us think again of those "triple goddesses" of the Gaelic tradition in Ireland, those famous triads sometimes called "triple Brigit" or "triple Macha."
While triple goddesses can be found in many cultures (Celtic, Roman, Greek, Hindu, and Mesopotamian, for example), the classification of the triplicity into a maiden-mother-crone format is distinctly modern.