This movement was a spontaneous one and followed different rules in different places. Some of the Culdees lived within the lay communities and married; others were hermits that re-emphasised the asceticism of the earlier anchorites. Still others founded new monasteries or became a distinct element in existing ones. They were particularly strong in the communities at Iona, Dunkeld and St Andrews, the successive administrative centres of the Church in the Dark Ages as well as at Monymusk, Scone and Abernethy.

      When the Church was reorganised in the twelfth century by King David I, the formal Culdee foundations in much of Scotland were uprooted and brought to an end by converting them to canons, both secular and regular. He did this because he believed that they were an unorthodox element of dissent which could not be tolerated by this Normalised patron of the Roman faith. But despite these efforts to extinguish their flame, the Culdees continued to exist in the Western Isles under the sponsorship of Somerled and his descendants. Later, Robert Bruce, whose cause was aided by most of the Highland institutions including the Culdees, repaid their support abundantly when he finally triumphed over the English occupiers. But eventually they passed into oblivion along with many of the other Highland institutions.