On 17 March 1778 the House of Commons began to consider the treaties between France and Britain's rebellious North American colonists. These had been signed early in February, and their formal communication to London signalled open French intervention in the War of American Independence. In the course of this debate Charles Jenkinson offered an incisive if pessimistic analysis of the predicament facing Britain. Her diplomatic isolation and accompanying political decline, he declared, were due to a wider and quite fundamental transformation:

Though acute, Jenkinson's analysis was too sanguine. During the 1770s Russia, Prussia and Austria, ‘the great military powers in the interior parts of Europe’, were already becoming the leading continental states: what he termed the ‘predominant powers’. Their political rise during the third quarter of the eighteenth century is the subject of this book.

The emergence of the eastern powers was a turning point in the evolution of the modern European states system. During the century after the Peace of Westphalia (1648) international relations had been shaped primarily by attempts to contain the French monarchy, the one true great power of that era.