European folklore or Western folklore refers to the folklore of the western world, especially when discussed comparatively. There is no single European culture, but the common history of Christendom during the Middle Ages and the Early Modern period has resulted in a number of traditions that are shared in many ethnic or regional cultures of Europe.
This concerns notably common traditions based on Christian mythology, i.e. certain commonalities in celebrating Christmas, such as the various Christmas gift-bringers, or customs associated with All Souls' Day.
The culture of Classical Antiquity, including mythology, Hellenistic religion and magical or cultic practice was very influential on the formative stage of Christianity, and can be found as a substrate in the traditions of all territories formerly colonized by the Roman Empire, and by extension in those territories reached by Christianization during the Middle Ages. This includes all of Europe, and much of the Middle East and North Africa. These traditions inherited from folk beliefs in the Roman era were syncretized with local traditions, notably Germanic, Celtic and Slavic. Many folk traditions also originated by contact with the Islamic world, especially in the Balkans and in the Iberian peninsula, which were ruled by Islamic empires before being re-conquered (in the case of the Balkans, partially) by Christian forces. The result of such cultural contact is visible e.g. in the tradition of the Morris Dance in England, an adaptation of the "moorish" dances of the late medieval period.
The result were the related, but regionally distinct, folk traditions as they existed in Europe on the eve of the Early Modern period. In modern times, and especially since the 19th century, there has been a lot of cross-pollination between these traditions, often by the detour of American folklore.