Alexandre de Prouville de Tracy (French pronunciation: [alɛksɑ̃dʁ də pʁuvil də tʁasi]; c. 1603 – 1670) was a French military leader, statesman, and the seigneur of Tracy-le-Val and Tracy-le-Mont in Picardy, France. A professional soldier, he was a regimental commander during the Thirty Years Wars, and was later appointed commissary general of French forces in Germany. In 1663, he was commissioned lieutenant-général of the French colonies in the Americas. In 1664, he led an expedition that expelled the Dutch from Guiana. The following year he sailed to New France where, in 1666, he led the Carignan-Salieres Regiment and Canadien volunteers in an invasion of the Mohawk homeland. He returned to France after reaching peace settlements with the Mohawk and the other Iroquois nations, and was appointed commandant at Dunkirk, and later governor of the Château Trompette in Bordeaux.

Alexandre de Prouville de Tracy, the son of Pierre de Prouville, bailiff of the citadel of Amiens, and Marie Bochart de Champigny, was born in Amiens c. 1603. He married Marie de Belin in Paris on 17 November 1624. Tracy had had a son, Charles-Henri, who died at Landrecies in 1655 during the Franco-Spanish War, and a daughter, Marie Chrisante. Tracy married his second wife, Louise de Fouilleuse, on 15 April 1657 at Saint-Eustache in Paris.

Tracy was a professional soldier who was recorded as a captain of light horse in 1632. After the French intervened in the Thirty Years War, he served as a regimental commander and fought in several battles including the Battle of Wolfenbüttel, the Battle of Kempen, the Battle of Freiburg, the Siege of Philippsburg, and the Battle of Nordlingen. He was appointed commissary general of the French army in Germany, and represented France in negotiations with Sweden and the Elector of Bavaria that led to the 1647 Truce of Ulm.

For many years the small French settlements on the north shore of the St. Lawrence River had been the subject of attacks by the Iroquois. By the early 1660s, the colony was on the verge of collapse. After receiving numerous pleas for help, Louis XIV took several steps to ensure the survival of New France, including sending professional soldiers.

In November 1663, Tracy was commissioned by Louis XIV as "lieutenant général throughout the length and breadth of the continental countries under our authority situated in South and North America." He was assigned two tasks: remove the Dutch from Cayenne (a former French colony in Guiana), and end the threat of the Iroquois to New France. The Carignan-Salières Regiment, commanded by Henri de Chastelard de Salières, was assigned to Tracy and would sail directly to Quebec while the lieutenant général was in the West Indies.

Tracy sailed from La Rochelle in February 1664 accompanied by Antoine Lefèbvre de La Barre, four companies of infantry from the Broglie, Chambellé, Orléans and Poitou regiments, and 650 settlers for the French colonies in the West Indies. Tracy's expedition captured Cayenne without opposition in May 1664. Leaving Le Barre and a garrison at Cayenne, Tracy sailed to Martinique where he reappointed the governor, then proceeded to Guadeloupe where a new governor was installed. He also installed a new governor to the island of Grenada called Monsieur de Vincent.

In April 1665, Tracy left Guadeloupe for the Gulf of St. Lawrence. After anchoring off Percé, Tracy and the soldiers that had accompanied him to the West Indies transferred to smaller ships and disembarked at Quebec on 30 June, 11 days after the first four companies of the Carignan-Salières had arrived from France. To avoid overcrowding in Quebec, Tracy sent the Carignan-Salières companies to build three forts along the Richelieu River, the main route used by the Mohawk in their raids on French settlements. Fort Richelieu was restored and Fort Sainte Anne was erected the following spring on Isle La Motte at the northern end of Lake Champlain. Salières and eight more companies of the Carignan-Salières landed at Quebec in mid-August. The newly appointed Governor General of New France, Daniel de Rémy de Courcelle, and the newly appointed intendant, Jean Talon, arrived with the final contingent of eight companies in mid-September.

Tracy quickly recognized that of the five Iroquois nations, the Mohawk were the most aggressive towards the French. For many years the Mohawk had raided French settlements, and had disrupted the flow of beaver pelts to Montreal by blockading the Ottawa and St. Lawrence Rivers. While the Onondaga, Oneida, Seneca, and Cayuga appeared willing to discuss peace, the Mohawk did not. In December 1665 an Onondaga and Oneida delegation arrived at Quebec to begin negotiations on behalf of themselves and the Seneca and Cayuga.