From Encyc

Prussia was a country in eastern Europe, bordering on the Baltic Sea. It integrated several other states to become Germany; the creation of the German Empire was proclaimed in 1870. Much of Prussia disappeared due to the peace settlements following World War I and World War II, and the land is now part of Russia or Poland.

Prussians were known for being aristocratic and militaristic.

Prussians allied with the British defeated Napoleon at the battle of Waterloo.

The earliest recorded history of the area reports a Baltic tribe known as the Prussians. They were pagans, and the christian Teutonic knights came in, took over, and brought in German settlers.