The incident brought out retainers from every corner, and they followed the bard in hot pursuit across country. But he went at such a pace that he would have reached the forest unscathed had it not been for a river in his path. While his beast was bounding across the torrent, Merlin slipped and fell into the fast current. The servants ranged themselves along the bank and captured him as he swam. They brought him home, bound him and handed him over to his sister.

Vita Merlini