The fighting between Anglo-American and French troops in North America raged for almost a year before any formal declaration of war was made. The British finally declared war on France on 20 May 1756. The French did not issue a formal declaration of war against Britain until June.
The French, however, were most concerned with the situation in Europe and the increasing military power of Prussia. The British took advantage of this concern. The British prime minister, William Pitt, negotiated an alliance with the Prussians and supported the Prussian army with large cash subsidies. While the French armies were preoccupied with the Prussians in Europe, Pitt concentrated British military power in North America. The Royal Navy, which had a numerical advantage over its French counterpart, blockaded New France. Consequently, the French found it very difficult to send additional troops to Canada.