The Battle of Fort Bull was a French attack on the British-held Fort Bull on 27 March 1756, early in the French and Indian War. The fort was built to defend a portion of the waterway connecting Albany, New York to Lake Ontario via the Mohawk River.

Lt. Gaspard-Joseph Chaussegros de Léry led his command consisting of forces from the Troupes de la Marine, Canadien militia, and Indian allies on an attack against Fort Bull on 27 March 1756. Shielded by trees they sneaked up to within of the fort. Léry ordered a charge at the fort with bayonets. They stuck their muskets into the narrow openings in the fort and shot the defenders. Léry repeatedly asked for their surrender. Finally, the gate was crashed in and the French and Indians swarmed in, killing everyone they saw. The French soldiers looted what they could and set the powder magazines on fire. The fort was burned to the ground.

Background The establishment of Fort Oswego (modern Oswego, New York) in the 1720s on the south shores of Lake Ontario (called Lac de Frontenac by the French) represented the first British toehold in what until then had been a "French lake", and was regarded as a major threat by the French.Chartrand, René Montclam's Crushing Blow, London: Osprey, 2014 page 4. The French had dominated the Great Lakes and with it the lucrative fur trade, and were determined to keep the Great Lakes for themselves. However, the 1720s-30s were a period of Anglo-French détente in Europe with both the duc d'Orleans, the Regent for the boy king Louis XV in France, and Prime Minister Sir Robert Walpole in Britain, being committed to a policy of peace.Chartrand, René Montclam's Crushing Blow, London: Osprey, 2014 page 4. Though the French protested at the establishment of Fort Oswego, saying the Great Lakes were part of New France, neither Paris nor London wanted a war over a fort in far-away North America, and so the matter rested for the moment. Versailles and Whitehall both agreed to an understanding that the British would not build any more forts on the Great Lakes in exchange for which the French tolerated Fort Oswego.Chartrand, René Montclam's Crushing Blow, London: Osprey, 2014 page 4. Fort Oswego was a remote frontier post located in the wildness, and in the words of the Canadian historian René Chartrand its "Achilles heel" was its supply lines.Chartrand, René Montclam's Crushing Blow, London: Osprey, 2014 page 4. The period of Anglo-French détente and peace which both Walpole and the duc d'Orleans pursued gave way to a period of war in the middle 18th century. France and Britain went to war in the inconclusive War of the Austrian Succession which was followed by the Seven Years' War, which began in North America in 1754 when the Virginia militia under the command of George Washington made a very unsuccessful attempt to expel the French from the Ohio river valley.

Following the failure of aggressive British campaign plans in 1755, a chain of forts along the Mohawk River riverway connecting the Hudson River to Lake Ontario were garrisoned during the winter of 1755–1756. The largest garrison was left at Fort Oswego, at the end of the chain, which depended on the others for its supplies. Two forts along the Oneida Carry were a key element of this supply chain. The Oneida Carry traversed an unnavigable section between what is now Rome, New York and Wood Creek that was between one and six miles long, depending on seasonal water levels. Wood Creek in its turn flowed into Oneida Lake, which flowed into the Oswego river that ran into Lake Ontario. On the other side of the Oneida Carrying Place was the Mohawk river, which flowed into the Hudson river, which in its turn flowed into the Atlantic Ocean. Fort Williams, on the Mohawk, was the larger of the two, while Fort Bull (modern Rome, New York), several miles north of Fort Williams on Wood Creek, was little more than a palisade surrounding storehouses. Fort Bull was garrisoned by a small number of men from Shirley's Regiment under William Bull, and held large quantities of military stores, including gunpowder and ammunition, destined for use in the 1756 campaign.Parkman, p. 374. Shirley's Regiment was a British Army regiment raised in New England with the majority of the soldiers coming from the colonies of New Hampshire, Massachusetts, Rhode Island Plantation, and Connecticut.Hagerty, Gilbert Massacre at Fort Bull: the de Léry expedition against Oneida Carry, 1756, Providence: Mowbray Company, 1971 page 21.

The assemblies of Pennsylvania and Virginia had only voted for enough money to defend their frontiers while the assemblies of the New England colonies had raised more men than what Shirley had requested after London had promised to pay off their debts if they would contribute to the war.Nester, William The First Global War: Britain, France, and the Fate of North America, 1756-1775, Westport: Greenwood Publishing Group, 2000 page 3. Shirley took the surplus men into the 50th Regiment of Foot, known as Shirley's Regiment.Nester, William The First Global War: Britain, France, and the Fate of North America, 1756-1775, Westport: Greenwood Publishing Group, 2000 page 3. The majority of the Shirely's regiment, who arrived in the Oneida Carry on 2 September 1755 were described by the American historian Gilbert Hagerty as "raw" and "untrained".Hagerty, Gilbert Massacre at Fort Bull: the de Léry expedition against Oneida Carry, 1756 Providence: Mowbray Company, 1971 page 21. Following the Battle of Lake George in September 1755, an Anglo-Haudenosaunee victory that saw the deaths of many of the warriors from the Six Nations who had been fighting on the British side, the Six Nations had pulled out of the war and declared their neutrality.Chartrand, René Montclam's Crushing Blow, London: Osprey, 2014 page 17. Shirley had ambitious plans for the 1756 campaign to take Fort Duquesne (modern Pittsburgh, Pennsylvania), Fort Rouillé (modern Toronto, Ontario), Fort Saint-Frédéric (modern Crown Point, New York), Fort Niagara (modern Youngstown, New York), and Fort Frontenac (modern Kingston, Ontario) with the campaign to culminate with taking Quebec City.Nester, William The First Global War: Britain, France, and the Fate of North America, 1756-1775, Westport: Greenwood Publishing Group, 2000 page 3. Since the New England colonies had voted more money and raised more men than did either Pennsylvania and Virginia, Shirley was focused on his plans for a campaign on the Great Lakes rather in the Ohio river valley.Nester, William The First Global War: Britain, France, and the Fate of North America, 1756-1775, Westport: Greenwood Publishing Group, 2000 page 3.

In the fall of 1755, Onondaga Indian travelers passing through Montréal mentioned to the French that the British were building two warehouses at the Oneida Carrying Place.MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 23 Pierre de Rigaud, marquis de Vaudreuil-Cavagnial, the Governor-General of New France, hired Ou8atory<sic>, an Oswegatchie of Oneida descent, to work as a spy, and find out what was going on at the Oneida Carrying Place.MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 23 Ou8atory returned to report that the British had built two supply-houses at the Oneida Carry, where they were stockpiling weapons, ammunition, bateaux, and other supplies for a spring offensive.MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 23

In early 1756 French military leaders in Canada decided to send a raiding expedition to attack Oswego's supply line. As the waters melted south of Lake Ontario an average of two weeks before the waters north of Lake Ontario did, the French feared the British would be able to launch an offensive in the spring to seize the main French forts, namely Fort Niagara and Fort Frontenac before the French forces in Montréal could come to their relief.MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 23 Vaudreuil chose to launch a preventive strike to destroy the British warehouses in the Oneida Carrying Place in the winter, and selected Lieutenant Gaspard-Joseph Chaussegros de Léry of the Troupes de la Marine to command the strike force.MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 23 Vaudreuil admitted that a winter strike was dangerous, going on to write in a report to Paris "...but the situation became urgent and I could not defer it without running the risk of being forestalled by the enemy at Niagara and at Fort Frontenac".MacLeod, D. Peter The Canadian Iroquois and the Seven Years' War, Toronto: Dundurn, 2012 page 24

The Troupes de la Marine were under the control of the Ministry of the Marine, which ran the Royal French Navy and all of the French colonies, dressed in distinctive white and blue uniform, and were recruited in France for an 8-year period of service.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 35. Though the men of the Troupes de la Marine were recruited in France, many of the officers were Canadiens.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 35. From the 1690s on, the sons of the seigneurs of New France had often been attached to the Troupes de la Marine as cadets starting in their teenage years before securing a commission in the Troupes de la Marine, meaning that many of officers of the Troupes de la Marine were familiar with frontier warfare and knew the Indian languages.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 pages 35-36. Chartrand wrote the Canadian-born officers of the Troupes de la Marine had "...devised an unwritten tactical doctrine that combined the best elements of European organization and discipline with the American Indians' extraordinary ability to travel great distances largely undetected and mount very fierce attacks".Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 35. In New France, all able-bodied men had to serve in the militia from the ages of 16 to 60 with every parish being organized into a company that practiced war games once every month.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 39. The French-Canadian militia wore no uniforms and received no pay, but received a gun, ammunition and other equipment from the French state when called up.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 40. As almost every Canadien man owned a gun, was a good shot having been using flintlocks from childhood onward and as many French-Canadians worked as voyageurs in the fur trade, they knew the frontier very well.Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 40. Chartrand called the militia of New France "fierce and outstanding bush fighters".Chartrand, René "Colonial and Militias of New France" pages 34-40 from Empires Collide edited by Ruth Sheppard, London: Osprey, 2006 page 40.