At the start, Iona was a part of the Gaelic kingdom of Dál Riata. The island was the site of a highly important monastery during the Early Middle Ages. According to tradition the monastery was founded in 563 by the monk Columba, also known as Colm Cille, who had been exiled from his native Ireland. Columba and twelve companions went into exile on Iona and founded a monastery there. The monastery was very successful, and played a large part in the conversion of the Picts to Christianity. It also had an influence on the Anglo-Saxon kingdom of Northumbria. Many other monasteries were founded in Scotland and Iona became the center of a great monastic system. The scriptorium produced many very important documents.