Charles de Batz de Castelmore was Count of Artagnan and therefore used that name. He was the right-hand man of King Louis XIV, the longest-reigning king (from 1643 to 1715) in the history of European monarchies.
D'Artagnan was the leader of the musketeers: an elite military corps that served as the personal bodyguard of the French king. He was killed in 1673 during the siege of Maastricht, when the French army attempted to capture the city. He was likely hit in the throat or chest by a musket ball."