The middle ages ended in 1453 with the fall of Constantinople, which coincided with the birth of the Renaissance in Italy having already taken place.

The Iroquois Confederacy was founded (most likely) in the 1500s, with the earliest record of the first capital being in 1609.

The United States itself was founded in the 1700s.

Their comment was correct, the Iroquois Confederacy was founded during the age of the Renaissance and our modern conception of America came much later