<P> Peace lasted in Canada until 1744, when news of the outbreak of the War of the Austrian Succession (King George's War in North America) reached Fort Louisbourg . The French forces went on the attack first in a failed attempt to capture Annapolis Royal, the capital of the British Nova Scotia . In 1745, William Shirley, governor of Massachusetts, led a counterattack on Louisbourg . Both France and New France were unable to relieve the siege, and Louisbourg fell to the British . With the famed Duc d'Anville Expedition, France attempted to retake Acadia and the fortress in 1746 but failed . The fortress was returned to France under the Treaty of Aix - la - Chapelle, but the peace treaty, which restored all colonial borders to their pre-war status, did little to end the lingering enmity between France, Britain, and their respective colonies, nor did it resolve any territorial disputes . </P> <P> Within Acadia and Nova Scotia, Father Le Loutre's War (1749--1755) began with the British founding of Halifax . During Father Le Loutre's War, New France established three forts along the border of present - day New Brunswick to protect it from a New England attack from Nova Scotia . The war continued until British victory at Fort Beausejour, which dislodged Father Le Loutre from the region, thereby ending his alliance with the Maliseet, Acadians and Mi'kmaq . </P> <P> Fort Duquesne, located at the confluence of the Allegheny and Monongahela Rivers at the site of present - day Pittsburgh, Pennsylvania, guarded the most important strategic location in the west at the time of the Seven Years' War . It was built to insure that the Ohio River valley remained under French control . A small colonial force from Virginia began a fort here but a French force under Claude - Pierre Pécaudy de Contrecœur drove them off in April 1754 . New France claimed this as part of their colony and the French were anxious to keep the British from encroaching on it . The French built Fort Duquesne here to serve as a military stronghold and as a base for developing trade and strengthening military alliances with the Aboriginal peoples of the area . </P> <P> In 1755, General Edward Braddock led an expedition against the French Fort Duquesne, and although they were numerically superior to the French militia and their Indian allies, Braddock's army was routed and Braddock was killed . Later that same year at the Battle of Lake George, the British General William Johnson with a force of 1700 American and Iroquois troops defeated a French force of 2800 French and Canadians and 700 Native Americans led by Baron Dieskau (Military commander of New France). </P>

How did france try to protect its land claims in the ohio river valley