In 1756, during the French and Indian War, the Lenape began to raid central Pennsylvania. When the colony organized a militia, its leaders appointed Weiser as a Lt. Colonel. Working with Benjamin Franklin, he planned and established a series of forts between the Delaware and Susquehannah rivers. When General Forbes evicted the French from Fort Duquesne in 1758, the threat subsided. Following its victory in the Seven Years War, Britain later gained all French territory east of the Mississippi River at the Treaty of Paris in 1763.