Edmund Flagg, Flagg's The Far West, 1836-1837…
“ Fort Chartres was erected by the French in 1720, as a link in the chain of posts which I have mentioned, uniting New-Orleans with Quebec; and as a defence for the neighbouring villages against the Spaniards, who were then taking possession of the country on the opposite side of the Mississippi, as well as against the incursion of hostile Indian tribes. The expense of its erection is said to have been enormous, and it was considered the strongest fortification in North America. ”
