The Seven Years' War (1756-1763) was caused by ongoing tension between Great Britain and France as well as Russian and Austrian fears of Prussia's growing power in Europe, and it resulted in further colonial supremacy for Great Britain and widespread acknowledgement of Prussia as a major European power. However, the great cost at which Prussia defeated its southern neighbor also restored Austria's military reputation after its humiliation in the War of Austrian Succession, and while the war paved the way for British domination in India, it forced caused Great Britain to pass laws to pacify its new Canadian possessions that ended up sparking the American Revolutionary War.
Although Austria and Britain had been allied before the Seven Years' War, the loss of Silesia to Prussia in the Austrian Succession convinced Austria that Britain was not a useful ally. Instead, they turned to France, Britain's historical rival, and Russia, who equally feared Prussia's rise. With Austria no longer friendly, Britain allied with Prussia to defend its holdings in Hanover, Germany. Sweden, Saxony and later Spain also fought with the Austrians while Portugal and other minor German states eventually joined Britain and Prussia.
Prussia had the strongest army at the time, and Britain had the largest navy. While the Austrian alliance had some successes, this strength at sea and on land combined with Russia's withdrawal after the succession of Tsar Peter III led to the triumph of the British and Prussians. It was the last major conflict in Europe before the outbreak of the French Revolution.