Musketeer of the Guard. Charles de Batz de Castelmore, also known as d'Artagnan and later Count d'Artagnan (c. 1611 – 25 June 1673), was a French Musketeer who served Louis XIV as captain of the Musketeers of the Guard. He died at the siege of Maastricht in the Franco-Dutch War. A fictionalised account of his life by Gatien de Courtilz de Sandras formed the basis for the d'Artagnan Romances of Alexandre Dumas, père, most famously including The Three Musketeers (1844). The heavily fictionalised version of d'Artagnan featured in Dumas' works and their subsequent screen adaptations is now far more widely known than the real historical figure.

D'Artagnan had a career in espionage for Cardinal Mazarin, in the years after the first Fronde. Due to d'Artagnan's faithful service during this period, Louis XIV entrusted him with many secret and delicate situations that required complete discretion. He followed Mazarin during his exile in 1651 in the face of the hostility of the aristocracy. In 1652, d'Artagnan was promoted to lieutenant in the Gardes Françaises, and fought at the Battle of Stenay in 1654, as well as in sieges at Landrecies and Saint-Ghislaine, then to captain in 1655. In 1658, he became a second lieutenant in the newly reformed Musketeers. This was a promotion, as the Musketeers were far more prestigious than the Gardes-Françaises.

D'Artagnan was famous for his connection with the arrest of Nicolas Fouquet. Fouquet was Louis XIV's finance commissioner and aspired to take the place of Mazarin as the king's advisor. Fouquet was also a lover of grand architecture and employed the greatest architects and artisans in the building of his Chateau Vaux-le-Vicomte. He celebrated the completion with a most extravagant feast, at which every guest was given a horse. The king, however, felt upstaged by the grandeur of the home and event and, suspecting that such magnificence could only be explained through Fouquet's pilfering the royal treasury, three weeks later had d'Artagnan arrest Fouquet. To prevent his escape by bribery, d'Artagnan was assigned to guard him for four years until Fouquet was sentenced to life imprisonment.

In 1667, d'Artagnan was promoted to captain-lieutenant of the Musketeers, the effective commander as the nominal captain was the king. As befitted his rank and position, he could be identified by his striking burgundy, white, and black livery—the colours of the commanding officer of the Musketeers. Another of d'Artagnan's assignments was the governorship of Lille, which was won in battle by France in 1667. D'Artagnan was an unpopular governor and longed to return to battle. He found his chance when Louis XIV went to war with the Dutch Republic in the Franco-Dutch War. After being recalled to service, d'Artagnan was subsequently killed in battle on 25 June 1673, when a musket ball tore into his throat at the siege of Maastricht.