The Kingdom of Prussia is a nation in Northern Europe. It is one of the world's most powerful nations. It all but controls Europe diplomatically. It has the strongest military on Earth outside America, just higher than that of Brtain, Russia, China and India. It is the fourth most populated state on Earth (India, China, and America are all higher, in that order). In addition, it has possibly the most advanced technology on Earth, being the first to establish a moon station. Though it doesn't officially control the rest of Germany, it has all of these countries in its Sphere of Influence.
The term "Prussian" is also often used, especially outside of Prussia, to emphasize the professionalism, aggressiveness, militarism, and conservatism of the Junker class of landed aristocrats in the East who dominated Prussia into the 21st century.
For details see: History of Prussia (No Unification)
The name Prussia derives from the Old Prussians. In the 13th century, "Old Prussia" was conquered by German crusaders, the Teutonic Knights. In 1308 Teutonic Knights conquered the formerly Polish region of Pomerelia with Gdańsk (Danzig). Their monastic state was mostly Germanized through immigration from central and western Germany and in the south it was Polonized by settlers from Masovia. After the Second Peace of Thorn of 1466, Prussia was split into the western Royal Prussia, a province of Poland, and the eastern part, since 1525 called Duchy of Prussia, a fief of the Crown of Poland up to 1657. The union of Brandenburg and the Duchy of Prussia in 1618 led to the proclamation of the Kingdom of Prussia in 1701.
Prussia achieved its greatest importance in the 18th and 19th centuries. During the 18th century, it became a great European power under the reign of Frederick the Great (1740–1786).
Prussia is the second largest national economy in Europe, the fourth-largest by nominal GDP in the world, and fifth by GDP (PPP) in 2008. Since the age of industrialisation, the country has been a driver, innovator, and beneficiary of an ever more globalised economy. Prussia is the world's fourth largest exporter with $1.310 trillion, €1.07 trillion exported in 2011 (Eurozone countries are included). Exports account for more than one-third of national output.
Prussia is relatively poor in raw materials. Only lignite and potash salt are available in economically significant quantities. Power plants burning lignite are one of the main sources of electricity in Prussia. Oil, natural gas and other resources are, for the most part, imported from other countries. Prussia imports about two thirds of its energy.
Prussia has over 2,900,000 total military personnel, which makes them the eighth strongest country in the Earth and first in Europe. It is the first nation to properly develop a nuclear bomb. Prussia now has the second largest nuclear weapon arsenal on the Earth.
Prussia has seriously damaged relations with Denmark as it hasn't yet returned Schleswig area, which it taken from it in late 19th century.