The more colourful story has it that the Lionheart saw a boy with a crossbow, using a pan to shield himself from arrows, and was consequently shot by the boy, while he was laughing at so daft a sight.
Actually, at the time he was besieging the castle of Chalus-Chabrol, where his entrails are buried in what still remains of the castle's chapel. Nobody really can explain why he was walking the perimeter that morning, without his mail - a mistake, some claim, a seasoned warrior like himself should not have made. The motives of the bowman, likewise, remain obscure - though as a defender of the castle, I don't think we need look much further. As he was not a knight, the code of chivalry does not apply to him. However, as the bowman who killed the king, who was repressing a revolt, at the time, I think they simply decided he could not live. Treason, or some such. They didn't look very kindly on that.
I do doubt the connection between priests and maces, as expressed. The crozier has always been the shepherd's staff, quite distinct from the formal maces some dignitaries carry in processions. In fact, priests were decidedly non-combatants, and were only allowed non lethal weapons for self defence, when present as chaplain or confessor on the battlefield. Shedding blood disqualified one for priesthood, much like how a church where blood has been shed must be reconsecrated.
Edited for clarification. And I just thought of the parallel with churches.