One account states that when Berno was abbot of Baume, he had such a good reputation, that William of Aquitaine gave him the monasteries at Deols and Massay. William was acquainted with Berno when he was abbot of Baume, and was supportive of the reformers who wanted to bring monasticism back to a stricter observance of the Benedictine rule. The Duke wanted to found a new monastery and asked Berno to be abbot. One story holds that when William asked Berno where the monastery should be founded, Berno asked the Duke to donate his favourite hunting lodge in Cluny; thereby making a sacrifice on his own part. The Duke protested and said, "Impossible, I cannot have my dogs removed“， and Berno then answered, "Drive out the dogs and put monks in their place, for thou canst well think what reward God will give thee for dogs, and what for monks." William gave part of his fiefdom of Cluny to Berno for the monastery. The founding of the monastery is dated to 11 September 909.