The Celts are one of the most well-known groups in Europe and one of the least understood. Depending on which classifications are used, the Celts are also one of the oldest civilizations in Europe. In the centuries before Christ, the Celts were spread out across much of continental Europe, and though they are mostly identified with Gaul, evidence suggests they also spread as far as Portugal. Though they were spread out across Europe before the height of the Roman Empire, most people associate the Celts with the British Isles today, particularly Ireland and Scotland. After they had been relegated to those smaller regions as a result of the Romans and other migrations, the culture of the Celts as it is currently understood began to congeal during the Early Middle Ages, and Celtic culture, folklore, and legend have all become inextricably intertwined with Irish history and British history as a whole.

Historically, Celtic cultures differ from their English and French neighbors in a number of ways, including social organization, language, values and economic systems, but one of the most captivating of these has always been their myths. Celtic Myths, which can be read in translation without needing special training in grammar, are more accessible than the Celtic languages, and unlike the other distinctive features that have faded over the centuries, myths still have their immediacy and power when read today. While much has undoubtedly been lost from the ancient Celts over time, medieval manuscripts help scholars understand how Celtic myths have reached the form they have today. Like many ancient belief systems, Celtic mythology shares Indo-European roots, meaning Celtic beliefs have cousins in related societies like the Norse, Greeks, Romans and Slavs, with a foundation of shared mythmaking that goes back several millennia.