Seven Years' War formally begins when Great Britain declares war on France.

The Seven Years' War, 1756 to 1763, was a Great Power conflict fought primarily in Europe, with significant subsidiary campaigns in North America and South Asia. The warring states were Great Britain and Prussia fighting against France and Austria, the respective coalitions receiving assistance from countries including Portugal, Spain, Saxony, Sweden, and Russia. Related conflicts include the Third Silesian War, French and Indian War, Third Carnatic War, Anglo-Spanish War (1762–1763), and Spanish–Portuguese War.

Great Britain, also known as the Kingdom of Great Britain, was a sovereign state in Western Europe from 1707 to the end of 1800. The state was created by the 1706 Treaty of Union and ratified by the Acts of Union 1707, which united the Kingdom of England and the Kingdom of Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands, with the exception of the Isle of Man and the Channel Islands. The unitary state was governed by a single parliament at the Palace of Westminster, but distinct legal systems—English law and Scots law—remained in use, as did distinct educational systems and religious institutions, namely the Church of England and the Church of Scotland remaining as the national churches of England and Scotland respectively.

The Kingdom of France is the historiographical name or umbrella term given to various political entities of France in the medieval and early modern period. It was one of the most powerful states in Europe from the High Middle Ages to 1848 during its dissolution. It was also an early colonial power, with colonies in Asia and Africa, and the largest being New France in North America geographically centred on the Great Lakes.