The Seven Years War in Europe, which began with the invasion of Saxony by Frederick the Great on 29 August 1756, was but one part of the world-wide struggle between Great Britain and France, which had commenced in the New World in 1754, though war between them was not officially declared until May 1756. Whilst the struggle of Prussia for existence was the main theme of the war in Europe, the operations on the Continent contributed to the larger struggle by influencing the energy and resources of the two contesting imperial Powers.

Prussia in 1756 was a new, half-finished country, composed of scattered fragments joined under one Crown, as a result of various marriages, by the chance of various deaths, and by conquest—a State without real frontiers, without geographical unity, inhabited by subjects who looked on the people of the next province as foreigners, and who owned a common allegiance to one thing alone, the person and the power of the sovereign. It lay scattered from the Niemen to the Rhine, divided into three principal groups: in the east was Prussia; in the centre the compact group of Brandenburg, Pomerania, Magdeburg, Halberstadt and Silesia; in the west the small territories of Minden and Ravensburg on the River Weser, Mark on the Ruhr, the Cleve duchies on the Rhine. On the borders of these possessions extended a fringe of contested lands, doubtful sovereignties, and potential legacies. Prussia had an artificial and precarious unity; its frontiers were one long law-suit; it had to win or lose, advance or retreat, extend or disintegrate—never satisfied since never secure.