Doreen Valiente in the context of "Bletchley Park"

Wicca (English: /ˈwɪkə/), is a modern pagan, syncretic, Earth-centred religion. Considered a new religious movement by scholars of religion, the path evolved from Western esotericism, developed in England during the first half of the 20th century, and was introduced to the public in 1954 by Gerald Gardner, a retired British civil servant. Wicca draws upon ancient pagan and 20th-century Hermetic motifs for theological and ritual purposes. Doreen Valiente joined Gardner in the 1950s, further building Wicca's liturgical tradition of beliefs, principles, and practices, disseminated through published books as well as secret written and oral teachings passed along to initiates.

Many variations of the religion have grown and evolved over time, associated with a number of diverse lineages, sects, and denominations, referred to as traditions, each with its own organisational structure and level of centralisation. Given its broadly decentralised nature, disagreements arise over the boundaries that define Wicca. Some traditions, collectively referred to as British Traditional Wicca (BTW), strictly follow the initiatory lineage of Gardner and consider Wicca specific to similar traditions, excluding newer, eclectic traditions. Other traditions, as well as scholars of religion, apply Wicca as a broad term for a religion with denominations that differ on some key points but share core beliefs and practices.

Wiccan views of divinity are generally theistic and revolve around a Goddess and a Horned God, thereby being generally dualistic. In traditional Wicca, as expressed in the writings of Gerald Gardner and Doreen Valiente, the emphasis is on the theme of divine gender polarity, and the God and Goddess are regarded as equal and opposite divine cosmic forces. In some newer forms of Wicca, such as feminist or Dianic Wicca, the Goddess is given primacy or even exclusivity. In some forms of traditional witchcraft that share a similar duotheistic theology, the Horned God is given precedence over the Goddess.

Some Wiccans are polytheists, believing in many different deities taken from various Pagan pantheons, while others would believe that, in the words of Dion Fortune, "all the Goddesses are one Goddess, and all the Gods one God". Some Wiccans are both duotheistic and polytheistic (and sometimes a combination of duotheism, polytheism, and pantheism) in that they honor diverse pagan deities while reserving their worship for the Wiccan Goddess and Horned God, whom they regard as the supreme deities. (This approach is not dissimilar to ancient pagan pantheons where one divine couple, a god and goddess, were seen as the supreme deities of an entire pantheon.) Some see divinity as having a real, external existence; others see the Goddesses and Gods as archetypes or thoughtforms within the collective consciousness.