The Most Ancient Lives of Saint Patrick/The Life and Acts of St. Patrick/Chapter 142
Of Saint Rodanus, the Herdsman of Patrick.
And Saint Patrick had a certain herdsman named Rodanus, and he was exceeding religious; and this man in his pastoral duty lived a hermit's life, and often being absorbed in prayer, he pastured the cows and the young calves together. And at the command of Saint Patrick, the whole herd was wondrously retained under his control, nor was any disturbance or confusion there among, for never did the calves approach their mothers, nor depart from them, other than at the bidding of Rodanus; and this he did by the authority and the power of his father, Saint Patrick. And he after a while learning letters, acquired sufficiently the knowledge thereof, and attaining the episcopal degree, he flourished during his life and after his death by manifold miracles.