Answer:
When France's expansion into the Ohio River valley brought repeated conflict with the claims of the British colonies, a series of battles led to the official British declaration of war in 1756.
Explination:
The French and Indian War began in 1754 and ended with the Treaty of Paris in 1763. The war provided Great Britain enormous territorial gains in North America, but disputes over subsequent frontier policy and paying the war's expenses led to colonial discontent, and ultimately to the American Revolution.