Nearly all 19th-century German historians made Frederick into a romantic model of a glorified warrior, praising his leadership, administrative efficiency, devotion to duty and success in building Prussia into a great power.

Frederick remained an admired historical figure through Germany's defeat in World War I, and the Nazis glorified him as a great German leader prefiguring Adolf Hitler, who personally idolised him.

Historians in the 21st century tend to view Frederick as an outstanding military leader and capable monarch, whose commitment to enlightenment culture and administrative reform built the foundation that allowed the Kingdom of Prussia to contest the Austrian Habsburgs for leadership among the German states.

[5] Frederick William I, popularly dubbed the "Soldier King", had created a large and powerful army that included a regiment of his famous "Potsdam Giants"; he carefully managed the kingdom's wealth and developed a strong centralised government.

[13] Nevertheless, Frederick, with the help of his tutor in Latin, Jacques Duhan, procured a 3,000-volume secret library of poetry, Greek and Roman classics, and philosophy to supplement his official lessons.

The king briefly threatened the crown prince with execution, then considered forcing Frederick to renounce the succession in favour of his brother, Augustus William, although either option would have been difficult to justify to the Imperial Diet of the Holy Roman Empire.

[43] Frederick formed the Bayard Order to discuss warfare with his friends; Heinrich August de la Motte Fouqué was made the grand master of the gatherings.

[56] Thus, upon succeeding to the throne on 31 May 1740,[57] Frederick declined to endorse the Pragmatic Sanction of 1713, a legal mechanism to ensure the inheritance of the Habsburg domains by Maria Theresa of Austria, daughter of Holy Roman Emperor Charles VI.

[48] Though Frederick justified his occupation on dynastic grounds,[60] the invasion of this militarily and politically vulnerable part of the Habsburg empire also had the potential to provide substantial long-term economic and strategic benefits.

Believing his forces had been defeated, Frederick galloped away to avoid capture,[66] leaving Field Marshal Kurt Schwerin to lead the disciplined Prussian infantry to victory.

[77] In late August 1744, Frederick's army had crossed the Bohemian frontier, marched directly to Prague, and laid siege to the city, which surrendered on 16 September 1744 after a three-day bombardment.

[92] During the ten years of peace that followed the signing of the Treaty of Dresden, Frederick prepared to defend his claim on Silesia by further fortifying the province, expanding his army,[93] and reorganising his finances.

[110] In the remaining years of the war, Frederick faced a coalition of enemies including Austria, France, Russia, Sweden, and the Holy Roman Empire,[111] supported only by Britain and its allies Hesse, Brunswick, and Hanover.

Frederick's army, which consisted of a substantial number of quickly recruited, half-trained soldiers,[117] attempted to check them at the Battle of Kunersdorf on 12 August, where he was defeated and his troops were routed.

[130] On 6 January 1762, Frederick wrote to Count Karl-Wilhelm Finck von Finckenstein, "We ought now to think of preserving for my nephew, by way of negotiation, whatever fragments of my territory we can save from the avidity of my enemies".

While the ensuing Treaty of Hubertusburg returned the European borders to what they had been before the Seven Years' War, Frederick's ability to retain Silesia in spite of the odds earned Prussia admiration throughout the German-speaking territories.

[190] Although Frederick's debasement of the coinage to fund the Seven Years' War left the Prussian monetary system in disarray,[189] the Mint Edict of May 1763 brought it back to stability by fixing rates at which depreciated coins would be accepted and requiring tax payments in currency of prewar value.

[193] One of Frederick's achievements after the Seven Years' War included the control of grain prices, whereby government storehouses would enable the civilian population to survive in needy regions, where the harvest was poor.

In his 1797 book, Mémoires pour servir à l'histoire du Jacobinisme (Memoirs Illustrating the History of Jacobinism), Barruel described an influential conspiracy theory that accused King Frederick of taking part in a plot which led to the outbreak of the French Revolution and having been the secret "protector and adviser" of fellow-conspirators Voltaire, Jean le Rond d'Alembert, and Denis Diderot, who all sought "to destroy Christianity" and foment "rebellion against Kings and Monarchs".

This programme created roughly 60,000 hectares (150,000 acres) of new farmland, but eliminated vast swaths of natural habitat, destroyed the region's biodiversity, and displaced numerous native plant and animal communities.

However the academy was in a crisis for two decades at mid-century,[268] due in part to scandals and internal rivalries such as the debates between Newtonianism and Leibnizian views, and the personality conflict between Voltaire and Maupertuis.

At a higher level Maupertuis, director of the Berlin Academy from 1746 to 1759 and a monarchist, argued that the action of individuals was shaped by the character of the institution that contained them, and they worked for the glory of the state.

[294] Emperor Joseph II wrote, "When the King of Prussia speaks on problems connected with the art of war, which he has studied intensively and on which he has read every conceivable book, then everything is taut, solid and uncommonly instructive.

"[295] Robert Citino describes Frederick's strategic approach: In war ... he usually saw one path to victory, and that was fixing the enemy army in place, maneuvering near or even around it to give himself a favorable position for the attack, and then smashing it with an overwhelming blow from an unexpected direction.

[299] According to Citino, "When later generations of Prussian-German staff officers looked back to the age of Frederick, they saw a commander who repeatedly, even joyfully, risked everything on a single day's battle – his army, his kingdom, often his very life.".

[305] Frederick derived little pleasure from his popularity, preferring instead the company of his pet Italian greyhounds,[306] whom he referred to as his "marquises de Pompadour" as a jibe at the French royal mistress.

[307] Even in his late 60s and early 70s when he was increasingly crippled by asthma, gout and other ailments, he rose before dawn, drank six to eight cups of coffee a day, "laced with mustard and peppercorns", and attended to state business with characteristic tenacity.

[315] For example, German historians often made him the romantic model of a glorified warrior, praising his leadership, administrative efficiency, devotion to duty and success in building up Prussia to a leading role in Europe.

[318] In an attempt to legitimise the Nazi regime, Propaganda Minister Joseph Goebbels commissioned artists to render fanciful images of Frederick, Bismarck, and Hitler together to create a sense of a historical continuum amongst them.

[321] After the war, the role of Prussia in German history was minimised and Frederick's reputation was downgraded in both East[322] and West Germany,[323] partly due to the Nazis' fascination with him and his connection with Prussian militarism.