In the early days of the neo-Pagan movement it was popular to call Wicca, "the old religion" based on the folk practices that were associated with it. The problem was, it wasn't the "old religion", not even close. Today most Pagan writers acknowledge this and openly discuss that which could not be questioned back then. That Wicca as promoted by Gardner, Sanders and even Sybil Leek in the sixties owed most of it's roots to middle ages occult practices of ceremonial magic and in practice the Order of the Golden Dawn. Just saying this forty years ago started a witch war immediately. In the rush to make Wicca something other than Gardnerian or Alexandrian the early work of anthropologist Margret Murray was also denounced, a big mistake. Dianic authors such as Merlin Stone hit much closer to the actual "old religion", in some cases almost right on the money but fueled by lesbian separatist mentalities of the time recast the older Goddess religion as for women only.
Wicca is big on the duality of God/Goddess and heterosexual sex energy as the basis of magical practice which meant that sexual minorities were largely unwelcome in Wiccan groups. Two groups sprung up to counter this in the seventies, the Dianics themselves and Leo Martello and his revival of Strega of southern Italy. Dr. Martello in particualr was the centre of a lot of different "witch wars" then, both opposing the male/female energy model and the "fam-trad" or family tradition school of Paganism at a time that it was starting to be widely acknowledged that Gardnerian Wicca was pretty much assembled by Gardner rather than ancient practices handed down in secret. Witch wars in those pre-internet days, were conducted by magazine articles and direct confrontations at various Pagan conventionss. It was slower and more deliberate back then since you had to wait for a response instead of firing off instant and oft ill thought out rebuttals common today. This eventually led to a concept of Pagan legitimacy coming from it's practice rather than it's history, that the Gods and Goddesses are essentially created by the belief in them. That invoking ancient Gods and Goddesses essentially re-recreated them or re-animated them. This neatly sidestepped the "my religion is older than yours and thus more legitimate" attitude many Christians threw at neo-Pagans.
The thing was, there actually was an Old Religion. In the late 1800's a number of works started to appear about the ancient Mother Goddess practices. They were fairly obscure and largely ignored by the mainstream historians and theologicans and by the 1920's were largely forgotten in the resurgence of the first wave of neo-Paganism taking place then that featured epic magical battles between occult practicioners, a spiritualist revival that swept the western world and open discussions of the reality of the "little people" and fairies that involved some of the best known writers and personalities of the day. While all this was going on, the newer, more scientific archeologists that were displacing the first treasure hunting rich hobbyist types were filling the back room shelves of museums around the world with Goddess figures and statuary and images. They were put on the back shelves because the anthropologists and ancient historians had their own cultural blinders on that required ignoring them to keep their narratives of ancient history based largely on classical era writings....but there were outbreaks of reality. Anyone familiar with anthropology has heard of Heinrich Schliemann and his search for Homer's Troy that was a watershed in archeology showing that the ancient legends were almost certainly remembrances of history instead of just fables. Less known is Sir Aurthur Even's discovery of the palace of Knossos on Crete and James Mellaart's later discoveries in Anatolian Turkey at Catal Huyak. Both Evens and Mellaart shocked the traditional views of ancient history to it's foundations in both realized they had found major Goddess cultures that featured total equality of the sexes, religions dominated by priestesses rather than priests and existed for very long periods of history without any signs of war being part of the cultures. Separated by thousands of years, the culture at Catal Huyak spanned the mesolithic to the neolithic (10000-5000 BCE) was far far more advanced than considered possible at the time. Both cultures, thousands of years apart, showed indications of Mother Goddess associations with bees, bulls, snakes and birds of prey as sacred to the Mother Goddess.
What happened next was feminist scholars started to re-examine the contents of those backroom shelves in museums around the world, often coming from scholarly backgrounds outside of history and archeology. Mainstream historians dismissed the Mother Goddess religion as sporadic and unrelated Goddess "cults" but the evidence clearly showed otherwise. Mainstream history has had narrative of linear advancement of human accomplishments and a clear progression in religion from pan-theism to mono-theism. This is completely false.and is based willful ignoring of the facts in evidence. The first known major religion of the world was the mono-theist Mother Goddess religion that can be traced by the spread of ideas associated with the work associated with women from Central Anatolia circa 10,000 BCE, to the middle east, Indus valley and the entire area surrounding the Mediterranean Sea. It is consistent in associated symbols and practices and most telling of all, when you translate the various local names of the Mother Goddess, they all translate into exactly that.......Mother Goddess, Mother of Gods or the Great Mother. It is now possible to trace the religion of the Mother Goddess in an unbroken line from Catal Huyuk to Rome. A religion that spanned ten thousand years of ancient history with probable roots much much further back when you factor in the paleolithic Goddess figures.
This was the old religion.