The longest-reigning King of France (5 September 1638- 1 September 1715)—and indeed the longest-reigning monarch of any European Great Powernote Several minor German princes reigned longer—known as Louis the Great or the Sun King. He was the most influential monarch of the 17th century. His most visible legacy is his ludicrously grand palace at Versailles.
Louis' impact on French history require a bit of context: namely, the fact that feudalism is decentralized. In theory, when the king says, "Go do this," everyone has to obey, but in practice the other lords, high lords, counts, viscounts, barons, dukes and princes have some leeway to hem, haw and etc. A feudal monarch thus relied on his own charisma and influence at least partially... And Louis's father, the thirteenth of his name, was a bit limp in this area, despite having The Three Musketeers working for him.
Louis XIV fixed this by turning himself into an "absolute monarch" and getting the nobles to wait on him hand and foot. Seriously, they treated him like they were teen girls and he was Justin Bieber. All this happened at Versailles, where Louis could keep track of who was fawning over him, reward them appropriately, and essentially keep them prisoner, able to stay only on his sufferance and not able to go home to their own fiefs and interfere with his rule. This was a genius political move, but it allowed Louis free rein (or free reign) as a dictator, which he exploited without compunction. Also, the problem with a Cult of Personality is that you need a successor of equal ability and charisma, or else the whole thing will collapse when you die. Louis XIV had no such, and his successor, Louis XV (actually his great-grandson) was nowhere near as effective, though it's his successor, Louis XVI (his grandson), who takes the cake in terms of screwing up whilst on the throne.
Civilization and its various iterations, in which Louis is sometimes a playable ruler
La Prise du Pouvoir par Louis XIV by Roberto Rossellini is a French film available on The Criterion Collection that shows how the King, in collusion with finance minister Colbert created Versailles and established himself as the absolute monarch. Historically accurate to a fault.
Be Careful What You Wish For: His aim of having Vetinari Job Security actually bit him in the ass during much of the War of the Spanish Succession, where most of his generals, while possessing Undying Loyalty to him, were complete idiots on the battlefield, and were summarily trounced when pitted against real generals like Marlborough and Prince Eugene. What saved him in the end was Britain pulling out of the war and Marshal Villars, another political appointee general (but a good one), winning at Denain well enough so that Louis would not have to negotiate with the Grand Alliance from a completely humiliating position.
Beam Me Up, Scotty!: Louis XIV never actually said "L'Etat, c'est moi" (I am the State). What he said was "L'Etat, Versailles"—which is close enough, since it roughly means "The King's Throne is the State." (This synchs up with his reported last words "Je m'en vais, mais l'État demeurera toujours.": "I am going, but the State shall always remain," as it means the monarch, whoever it is, is the state.)
Big Eater: Had a stomach thrice the average size of his time and presumably bigger than the nowadays average size. Hence this trope.
Create Your Own Villain: From Louis' perspective, rejecting Prince Eugene's request to command a company of soldiers for not showing him the proper respect turned out to be an extremely bad move.
Didn't Think This Through: Sorta. Abrogating the Edict of Nantes was a long-thought move, but he didn't foresee it would deprive France of numerous useful and crafty people.
And then there was the system of government he established. While it put an end to noble rebellions and abuse of power, it depended on a strong, competent monarch to keep everything running. Louis XIV certainly fit the profile, but when Louis XV and XVI took over, their ineptitude eventually led to the French Revolution.
Whilst it would have taken godlike foresight to see how poor this decision was, rejecting the young, gawky, and insolent Prince Eugene of Savoy for a military command turned out to be a very poor decision. He would go on to be the most successful military commander in Austrian history, denied the chance to serve in Louis's army.
The Emperor: Non-evil variant, of course. Despite not owning the title, he was one of the most powerful sovereign of his time in the whole world, if not the most powerful.
Long Runner: He ruled for 72 years (1643-1715), the longest reign in France's history and one of the longest in World history. Outlived his first wife, most of his mistresses, his little brother, his son, his grandson and his eldest great-grandson. He died at age 77.
Mama's Boy: He was famously very close to his mother, Anne of Austria.
Morton's Fork: Louis XIV's actions in the Succession Crisis preceding the War of Spanish Succession can be viewed as this, as Louis could either: A) Accept Carlos II's will, that left all of Spain to his Grandson, provoking war with all of Europe's major powers or, B) Refuse and let Spain and its rich colonies fall into the hands of the Austrian Habsburgs, which would put France in danger.
Napoleon Complex: Had this in spades even before the Trope Namer. Unlike the actual Napoleon Bonaparte—who was actually of average height—Louis really was short, about 5'5", and wore 4-inch heels to get around that (incidentally starting a men's fashion for heels that through the convoluted history of fashion is probably the origin of the modern female fashion...yes).
The Power of the Sun: Louis was nicknamed the "Sun King", based on the fact that everything in his court supposedly revolved around him. During most of his reign, he was also the most powerful man in Europe.
Really Gets Around: Not as much as his great-grandson (who was a sex maniac by any standard), but Louis XIV did have several mistresses. One even secretly became his wife (to whom he stayed faithful) !
Royals Who Actually Do Something: Besides being a very dedicated and competent ruler, he frequently led his troops on the battlefield, though his Camp Gay little brother was better at it than him. Louis was not amused and quickly deprived his brother of any military command.
Louis XIV: If I told you to jump from the cliffs of Brest, you would do it.
Colbert: (*turns his back on Louis - a huge taboo - and walks away)
Louis: Where are you going?
Colbert: To learn how to swim.
Vetinari Job Security: Louis used this to his advantage by seeking to control his nobles by having them wait on him, thus increasing his authority. The nobles, trying to gain more honor via Louis' favor would go to great efforts to simply get the honour to, say, be appointed the one in charge of Louis' wardrobe.
This occasionally bit him in the arse, e.g. when his need to have everyone rely on him forced him to fire some of his most competent generals (including, as mentioned above, his own brother).
Workaholic: Became his own prime minister and personally ran the business of the kingdom himself, whereas his father appointed cardinals like Mazarin and Richelieu to handle much of the business of statecraft.
Worthy Opponent: No less a figure than Napoleon Bonaparte declared Louis to be "the only King of France worthy of the name." Bear in mind that the Bourbons were just about the last people Napoleon would have any reason to compliment.
The Wrongful Heir to the Throne: some people believe the Man in the Iron Mask is Louis' twin brother, wrongly imprisoned as to not get in the way of Louis'ascension.