Knowing the Face of God, Tim Stafford, p. 121ff
The story is told about the baptism of King Aengus by St. Patrick in the middle of the fifth century. Sometime during the rite, St. Patrick leaned on his sharp-pointed staff and inadvertently stabbed the king's foot. After the baptism was over, St. Patrick looked down at all the blood, realized what he had done, and begged the king's forgiveness.
Why did you suffer this pain in silence, the Saint wanted to know.
The king replied, "I thought it was part of the ritual."