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Although the war did not officially begin until 1756, hostilities between the warring countries had been growing for many years. The two rival countries, Prussia and Austria, battled on a small scale for five years over who would control the Province of Silesia. Frederick II of Prussia and Maria Theresa of Austria were the respective leaders, both unwilling to give up Silesia. During the first half of the war, Prussia seemed to be on the winning side. As time progressed, France, Russia, Saxony and Sweden joined with Austria in their cause and the winning factors turned slightly and now favored Austria. Britain was the lone country to ally Prussia. The first day when The Seven Year's War began Frederick of Prussia invaded the German state of Saxony. His reasons, besides the fact that Saxony was an ally of Austria, were that it was wealthy and a good location to post his armies. Within days, Frederick's army had taken over Saxony and the war was in full scale. Through the Treaty of Hubertusburg, Frederick maintained his possession of Silesia and confirmed Prussia's stature as a major European power.
Prussias' early triumph led them through the following years with confidence. They fought hard and won many battles in the years following the Saxony invasion, most notably over France and Austria. Frederick conducted brilliant warfare against his extremely powerful enemies. Nevertheless, their supply of soldiers was steadily decreasing and in time, Austria's forces began to take over the war. In June of 1762, with the allied forces surrounding Prussia's army, the Russian empress Elizabeth died. Peter III took over Russia and immediately pulled out of the war along with Sweden. Austria's other allies were too weak to take over Prussia without Russia's aid. This turn of fate saved Britain and Prussia and allowed them to sign a peace treaty with Peter III.
Meanwhile, Britain had crushed France's overseas empire by capturing Canada and much of India.
