The Hiberno-Scottish mission was a mission initiated by Gaelic monks from Ireland and the western coast of modern-day Scotland, which spread Christianity and established monasteries in Great Britain and continental Europe during the Middle Ages. The mission originated in 563 with the foundation of Iona by the Irish monk Saint Columba, and was initially concerned with ministering to the Gaels of Dál Riada and converting the northern Pictish kingdoms. Over the next centuries the mission grew in power and influence and spread through Anglo-Saxon England and the Frankish Empire. The early mission is often associated with the Christian practice known as Celtic Christianity, which was distinguished by its organizations around monasteries rather than dioceses and certain idiosyncratic traditions, but the desire to maintain a relationship with the Holy See saw their missions take on a more Roman character.