depending on the teller of the tale , he was the youngest son of an extremely poor family of farmers or miners , and he had shown the first signs of his preternatural abilities when , as a lad no taller than a goat , he could wield a spade or a pickax with twice the strength of a burly labourer , provoke terror in the most aggressive sheepdogs , and beat older , bigger children black and blue for belligerence seemed to run in little royens blood ; what was more , the boy was invulnerable to illness and pain that would have a grown man writhing and moaning in his sickbed .