At the beginning of the twentieth century, an incredible thing was happening. Scientific discoveries were being made that undermined the most popular creation story in the world, that of the Hebrew scripture. The remains of animals that humans had never seen before were being discovered, and a man named Charles Darwin was suggesting that animals may not exist today as they did many years ago. The foundation of traditional religion had been cracked, and many people turned away from Christianity and other traditional faiths.
Around this same time, an archeologist named Margaret Murray published a book called The Witch Cult in Western Europe. It detailed the spiritual life of ancient cultures of the European continent, and labeled the members of these cultures as Witches. They were people who followed a fertility-cult religion and who performed magic. This is what led to the label of Witch from Murray's pen--as a member of turn of the century society, magic and witchcraft were linked in her mind. Unfortunately, even though she was a skilled archeologist, she followed the "witch" strain to another end: she wrote in her book that these cults worshipped the devil. However, in her second book on this subject, The God of the Witches, she retracted her statement that these societies worshipped the devil and explained that is was a hunter, beast-like god of fertility and nature that they paid homage to. These two books together gave an incredibly detailed and eye-opening explanation of ancient culture and religion that had not been widely available before.
Closer to the middle of the 20th century, the effects of Murray's books were apparent in the writing of Gerald Gardner. He published a book called Witchcraft Today. In it, he claimed that he had found one of these ancient societies, still flourishing and practicing their religion, on the Isle of Man. He was initiated into their cult and learned their practices. They were much like those detailed in the books of Margaret Murray. In retrospect, it was likely that Gardner had never found such people, and that his book was based on Murray's writings and his own fantastical ideas. However, he was the first person to widely use the word Wicca, after the old English word for Witch. Both this name and his ideas caught on, and the Wiccan religion was begun. The earliest Wiccans were Gardnerians, coven members that followed the ideas set forth by Gardner.
Like the Gardnerians, the overwhelming majority of early Wiccans were traditionalists. They were members of covens and followed the ideas set forth by Gardner (or Alexander in the case of Alexadrians, etc.), including a much heavier emphasis on heirarchy and fertility than we will see in later years.