Once gone up on the throne, it continued to be interested in the things of the spirit and was surrounded by a small court of intellectuals, among whom Voltaire appeared of 1750 to 1753. He wanted to be the model of the “enlightened despot” and promulgated an edict of tolerance (1740), abolishes torture, reformed justice, developed teaching, industry and the trade, continued the company of settlement and colonization of its territories started by its predecessors.  

However, the happiness of its subjects worried it less than the size of Prussia. As a true heir to Hohenzollern, it attempted to make of its army (200 ' 000 volunteers and conscripts framed by an excellent body of officers recruited in the nobility) a frightening machine of war, which envied to him whole Europe. Thanks to it, it seized Silesia, during the war of succession of Austria and was made some confirm the possession with the treaties of Breslau (1742), Dresden (1745) and Aachen (1748).

During the Seven Year old war, it however undergoes some serious failures. It for the first time rectified the situation in 1757 thanks to two victories - Rossbach on the French and Leuthen on the Austrians -, where its exceptional military engineering continued. In 1762, Prussia, at the edge of the disaster, was saved only by the death of the tsarina Elisabeth I, which Pierre III succeeded, large admiror of Frederic II.

In 1772, it obtained, with the first division of Poland, from which it had taken the initiative, Polish Prussia except for Thorn and of Dantzig. With its death, the Prussian power was considerable and the German unit was going to be able to be built on its bases, at the next century.