While a camel could move a quarter ton and ox-drawn carts around a ton, even the earliest bulk ships could move several hundred tons at a fraction of the price per ton. The Romans famously imported most of their capital’s food from Egypt. Remember those better-than-world-class Roman roads? In 300 CE it cost more to move grain 70 miles on those roads than it did to sail it some 1,400 miles from Egypt to Rome.
