" It was rare for Richard to have hands clear of broken blisters or his body unbruised. When he was weak of will, as his brother was weak, when he wanted to gorge his starving frame or drink himself to oblivion, or simply to allow all his bruises to heal to spare himself from pain, he would recite the words a Benedictine monk had taught him for such times:
'Non draco sit mihi dux. Vade retro Satana.'
'The dragon is not my master. Get the behind me, Satan.' The words had become a talisman and saying them brought him back to calm. Richard lived in pain and his flesh was in opposition to his will. Yet he would prevail, because all flesh failed, whereas the will was a sea deep enough to drown "

― Conn Iggulden , Ravenspur: Rise of the Tudors (The Wars of the Roses, #4)