War is formally declared between England and France!
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. As time progressed, France, Russia, Saxony and Sweden joined with Austria in their cause. Britain was the lone country to ally Prussia.
Louis Joseph, Marquis de Montcalm, Gozon de St. Véran, arrived in Quebec in May, 1756. He soon became aware that the most danger to Niagara form the British lay through Oswego. With this in mind, he set out to isolate and conquer the British post.
In the campaign of 1756, either the advancing French or the retreating British destroyed practically all units of the system of small British posts painfully erected to guard the approaches and portage of the Great Carrying Place between the Hudson-Mohawk River system and Lake Ontario through Wood Creek, Oneida Lake, the Oneida and Oswego Rivers.
The most spectacular of these losses was British Fort Bull, captured with it's garrison and 4,000 pounds of powder by skate-and-snowshoe raiders from La Présentation. This force of 360 Indians, Canadians, and French regulars under Lieutenant Ghtmlard-Joseph Chaussegros de Léry, captured Fort Bull, thus cutting the supply line to Fort Oswego.