This story appears in the March/April 2017 issue of National Geographic History magazine.

Throughout history, small states have come out of nowhere, and rapidly become great powers. This was the case of Prussia, a former duchy that in the early 1700s emerged from the shadow of Poland and the Holy Roman Empire. Growing to encompass much of northern and central Europe, Prussia was led to new heights by Frederick II.

Ruling from his new capital, Berlin, Frederick’s father, Frederick William I, was Prussia’s second monarch. During his reign (1713-1740), Frederick William built up a large, well-trained army from his small population. His acquisition of new lands made Prussia prosperous as well as formidable.

Frederick William I was a man of iron discipline, whose military obsession bordered on the fanatical, but his son seemed to be his exact opposite. Young Frederick was a talented musician, a lover of philosophy and poetry, and an admirer of the French, whose language and culture would deeply mark his future reign. Considering those pursuits effeminate, the king abused his son both emotionally and physically. In 1730 Frederick attempted to run away to England, but the plot was foiled and Frederick imprisoned. His father not only had his main accomplice (and perhaps his lover), the officer Hans Hermann von Katte, beheaded, but also forced Frederick to watch the execution.

View Images Frederick II’s sexual orientation is debated by historians, some of whom argue that he was homosexual. Frederick’s lack of interest in women was well known. Arranged by his tyrannical father, his marriage to Elizabeth Christine of Brunswick-Bevern was loveless: Frederick once described his wife as “this sour subspecies of the female sex” and effectively banished her from court. At Sanssouci, his circle consisted exclusively of men, many young and handsome. But conclusive proof of Frederick’s affairs is elusive: Some historians believe he lost sexual function in his youth from an attempt to treat a sexually transmitted disease. Photograph by Album

Soldier and Scholar

After Frederick William I’s death in 1740, his son and successor took the throne and surprisingly went on to achieve stunning military victories, consolidating Prussia’s role as a great European power. Frederick II, later “the Great,” managed to combine his military prowess with the French ideals he had absorbed through his education, establishing the model for enlightened despotism in Europe.

Like many great leaders, however, Frederick II was something of a contradiction. Among the many books he wrote in French was a denunciation of Niccolò Machiavelli, in which Frederick sternly criticized the 16th-century Italian author’s cynical stratagems to exploit power. Yet Frederick II was not without a streak of Machiavellian practicality himself. For all his love of French poetry and the fine arts, he did not shy away from militarism to strengthen the Prussia he inherited from his father.

In 1740 he stunned Europe by launching a surprise invasion of the wealthy region of Silesia, which then belonged to Habsburg Austria. This action triggered the War of the Austrian Succession, which lasted eight years and brought Frederick’s diplomatic and military skills to the fore. The Peace of Aachen ended the conflict in 1748 and formally ceded Silesia to Prussia, a triumph for the new Prussian king.

The Philosophers’ Palace

In the late 1740s Frederick began building an extravagant summer palace in Potsdam, near Berlin. In homage to his Francophile leanings, it was given the French name of Sanssouci, meaning “carefree.” Frederick envisioned his estate as a kind of Versailles for Berlin, a place given over to the enjoyment of the arts and the exploration of the latest trends in Enlightenment thinking.

Intellectuals traveled from all over Europe to Sanssouci, among them mathematician Pierre-Louis Maupertuis, whom Frederick summoned to head the Berlin Academy. Maupertuis’s ostentatious wigs and high-pitched voice made quite an impression, as did his intellect. In the 1730s, he had proven that the world was flattened at the poles, just as Isaac Newton had predicted.

View Images A King’s Best Friend An unabashed dog lover, Frederick II is credited with coining the phrase “man’s best friend” to describe one of his greyhounds. The phrase appeared in a 1789 biography, published after his death. Frederick wanted to be buried next to his dogs at Sanssouci, but his heir entombed him in Potsdam next to his hated father. After the reunification of Germany, Frederick the Great finally got his wish: He was interred alongside his canine companions in 1991. Photograph by Bridgeman/ACI

The French philosopher Julien Offroy de La Mettrie also took up residence at Sanssouci. His famous book, L’Homme-machine (The Human Machine) argued for a materialistic—and, some argued, an atheistic—understanding of human motivations. Mettrie was one of a number of colorful and controversial houseguests at Sanssouci, which also included the French writer Marquis d’Argens. Among other works, the marquis is credited with Thérèse philosophe, a best-selling 1748 novel that blended pornography with philosophical musings on female sexuality and religious power in society.

But the most coveted of all the jewels in Frederick’s court was undoubtedly François-Marie Arouet, better known by his pseudonym, Voltaire. By the time Frederick was building Sanssouci, Voltaire was the most famous intellectual in Europe, loved and hated for his stinging attacks on power and his rallying cry for religious freedom and rational thought. He arrived in Prussia in 1750, grieving the death of his lover, the Marquise du Châtelet. The French king Louis XV, contemptuous toward the Enlightenment thinkers, was said to have declared: “One more madman in the Prussian court and one less in mine.”

A Singular Court

Frederick and his international coterie often dined together, talking late into the night. The atmosphere that he cultivated at Sanssouci reflected his fondness for men and his distaste for women. Voltaire commented: “Neither women nor priests ever entered the palace. In a word, Frederick lived without religion, without a council, and without a court.” The king, Voltaire wrote, flaunted his predilection for young officers. “When His Majesty was dressed and booted, he had two or three favorites come, either lieutenants of his regiment, or pages, or hajduks [Hungarian infantry], or young cadets. They took coffee. He to whom the handkerchief was thrown stayed another quarter of an hour in privacy.”

Voltaire’s role at Sanssouci was to act as a sort of literary adviser and editor to Frederick, polishing his poetry and suggesting ways to improve it. Because Frederick’s poetic talent was mediocre at best, the working relationship with the man he once gushingly named the Solomon of the North, soured. “Will the king never tire of giving me his dirty laundry to wash?” Voltaire quipped one day to La Mettrie, who immediately reported the comment to the king. “I shall need him for another year,” Frederick is said to have responded. “We shall squeeze the orange and throw the peel away.” In the end, having fallen out with the mathematician Maupertuis, Voltaire fled Prussia in 1753. Enraged, Frederick ordered him put under house arrest in Frankfurt before Voltaire finally made it to safety in Geneva.

View Images The garden facade of the Palace of Sanssouci, Potsdam, near Berlin, built by Frederick II of Prussia in the 1740s. Photograph by Sergey Kuznetsov, Age Fotostock

Bloodied, not Bowed

Following the flight of his most valued philosopher, Frederick threw himself back into military pursuits. The Seven Years’ War (1756-1763) was triggered by the alliance formed among Russia, Austria, and France, with the aim of curbing the growing power of both Great Britain and Prussia. At first Frederick won resounding victories, defeating France and Austria at Rossbach in 1757. Later that year, at Leuthen, he overcame difficult conditions to beat the Austrian army.

View Images Military Marvel Frederick II personally led his forces into battles, earning him a reputation for bravery as well as an expert, even genius, commander. His greatest triumph was in 1757 at Leuthen against an army twice the size of his own. Napoleon later regarded that battle as “a masterpiece of movements, maneuvers, and resolution.” Photograph by AKG/Album

The war later turned against the Prussian sovereign, when Russia occupied Berlin. His army battered, and his state coffers severely depleted, Frederick nevertheless battled back to retake lost territory, creating the impressive reputation for Prussian military resilience.

The Seven Years’ War had major global ramifications that extended to North America, where British colonies sparred with the French and indigenous peoples. In 1763, when the conflict ended, Britain was emerging as a world power, and Prussia’s standing in Europe was considerably boosted.

Having proved his leadership, Frederick kept faith with his Enlightenment ideals until the end of his reign. In his “Essay on the Forms of Government” (1777), he argued that a prince “is merely the principal servant of the State. Hence, he must act with honesty, wisdom, and complete disinterestedness in such a way that he can render an account of his stewardship to his citizens.”