Complex sentence: The original wooden fort was built in 1718-1720 by a French contingent from New Orleans, led by Pierre Dugué de Boisbriand, when administration of the Illinois Country was moved from Canada to New Orleans.
Split into simpler sentences: The original wooden fort was built in 1718-1720 by a French contingent from New Orleans, led by Pierre Dugué de Boisbriand. When administration of the Illinois Country was moved from Canada to New Orleans.