"Wicca, as you practice the religion today, is a new religion, barely fifty years old. The techniques you use at present are not entirely what your elders practiced even thirty years ago. Of course, threads of 'what was' weave through the tapestry of 'what is now.' ...in no way can we replicate to perfection the precise circumstances of environment, society, culture, religion and magick a hundred years ago, or a thousand. Why would we want to ? The idea is to go forward with the knowledge of the past, tempered by the tools of our own age" (http://www.religioustolerance.org/wic_hist.htm).
When Wicca is considered a new religion, it's origins can be seen in various works. The main people who initiated the movement for the popularity of Wicca were Charles Leland, Margaret Murray, and Gerald Gardner. Some people argue that before Margaret Murray's book The Witch Cult in Western Europe (1921) and The God of the Witches, Wicca did not exist. This sect of the public believes that Murray initiated Wicca and Gardner helped increase the popularity of it with his book High Magic's Aid (1949). B.A. Davis-Howe claims for certain that: "Wicca was invented by Gerald Gardner (and possibly some other folks), probably around fall equinox 1939. The seed of inspiration for this invention was Margaret Murray's books, The Witch Cult in Western Europe and The God of the Witches" (http://www.wiccanet.net/wicca/reading_room/66.html).