1648 in the context of "Leap year starting on Wednesday"

The Royal Prussian Army (1701–1919, German: Königlich Preußische Armee) served as the army of the Kingdom of Prussia. It became vital to the development of Prussia as a European political and military power and within Germany.

The Royal Prussian Army had its roots in the core mercenary forces of Brandenburg–Prussia during the long religious strife of the Thirty Years' War of 1618–1648. Elector Frederick William (1620–1688, reigned 1640–1688), developed it into a viable standing army, while King Frederick William I of Prussia (1688–1740, reigned 1713–1740), dramatically increased its size and improved its doctrines. King Frederick the Great (1712–1786, reigned 1740–1786), a formidable battle commander, led the disciplined Prussian troops to victory during the 18th century Silesian Wars and greatly increased the prestige and military reputation throughout Europe and among the hodge-podge array of various German states kingdoms, duchies, principalities and free cities of the leadership in the East of the rising Kingdom of Prussia.