Complex sentence: In 806, Vikings massacred 68 monks in Martyrs'Bay, and Columba's monks returned to Ireland, and a Monastery at Kells: other monks from Iona fled to the Continent, and established Monasteries in Belgium, France, and Switzerland.
Split into simpler sentences: In 806, Vikings massacred 68 monks in Martyrs'Bay, and Columba's monks returned to Ireland, and a monastery at Kells. Other monks from Iona fled to the Continent, and established monasteries in Belgium, France, and Switzerland.