The use of blunt weapons to avoid the prohibition on shedding blood is a 19th century myth that made its way into D&D.Odo of Bayeaux, half brother of William the Conqueror. Norman knight, bishop of Bayeaux, used a mace in battle so as not to violate church law on clergy spilling blood. Shown on the Bayesux tapestry. The mace thing was a common loophole for fighting clergy of the time. He was the most famous example.