Celtic Christianity refers to the form of Christianity practiced in Celtic-speaking regions during the Early Middle Ages, marked by distinctive liturgical customs, monastic practices, and regional diversity. Scholars debate its categorization, with some dismissing the idea of a unified "Celtic Church" in favor of "Insular Christianity," highlighting its integration into Latin Christendom. Features such as unique methods for calculating Easter, specific monastic hairstyles, and particular penitential rituals set it apart, although regional distinctions remained.
Authors like Patrick Wormald have challenged misconceptions about a Roman-Celtic conflict, while others, such as John Rhŷs, have examined the interaction between Celtic pagan traditions and the adaptation of Christian beliefs. Contemporary scholarship emphasizes that Celtic Christianity was not inherently opposed to Rome but represented localized modifications within a wider orthodox context, influenced by historical and geographical factors. Its influence continues through monastic connections and cultural blending, demonstrating a dynamic balance between tradition and change.