Wicca, as practised today is, effectively a pagan fertility religion or belief and in that way it has much in common with the most ancient ritual practises of such religions.
However, it is simply untrue that that link is or was unbroken. The late period of the Western Roman Empire saw the rise and establishment of the great religion Christianity throughout the Roman Empire under the reign of Emperor Constantine.
Over the centuries, pagan religions and practises were discouraged. However, many of the pagan rituals, festivals and deities were syncretized with Christianity in various forms. Indeed, Christianity has been remarkably accommodating of local belief systems as Modern African versions shew us.
Like Christianity, modern Wicca is comprised of several schools of thought, each with its own idea of what is true Wicca. This is simply a result of the way we folk are ... all different. It is neither good nor bad that it is so.
Some Wiccans keep themselves to themselves and seek out knowledge to practise the craft in their own way sometimes as a local healer, or even sometimes as a successful businessman or woman. Others, practise the craft in a group or coven. Sometimes these are simply groups of friends, folk who have known each other for some time and other covens invite members to join.
There is no hierarchy or overarching body or bodies who oversee those engaged in the practise of Wicca. This freedom may appeal to many who like to express their individual and creative spirit. This does carry dangers, in that a criticism levelled is that with folk who believe in everything believe in nothing. This criticism does not hold up in a general sense though doubtless the work of some individuals can be held as such.
A large section of the Wiccan community are devoted to acting in harmony with Nature. They too, are divided into two main groups. One of these groups has much in common with Buddhism and generally adopts a gentle, almost feminine approach to their spirituality and to their place in the universe. They will often be committed to vegetarianism or veganism and be involved in conservation of the environment issues.
The other group in this section reflects their practises in such a way as to seek to incorporate their spiritual connection to Nature with being the human that they are. They may display little outward signs of their wiccan beliefs in their everyday life. They are often found in the higher reaches of business and politics. Many Kings, Queens and Princes through history have practised one or other version of Wicca, albeit in private. The magic of wicca is very real, powerful and can lead to great achievements.