Modern international trade basically runs on standardized shipping containers and the infrastructure developed to handle them. Looking at just a small part of it, using crane to unload full containers and move directly from ship deck to truck bed, or vice-versa, and allowing containers to be packed in a space-filling arrangement on deck, is just way more efficient than individually packing items in a ship's hold or truck trailer, isolating the complex bits of loading and unloading to only the very ends of the transport chain.
But... modern shipping container infrastructure basically depends on access to large quantities of cheap metal--for the containers, and the enormous port cranes that handle them.
It seems to me that an analogous system could have been developed significantly earlier in history, however, using wooden crates of standardized size (much like we still use standardized wooden pallets), and smaller-scale wooden cranes. In reality, wooden harbor cranes have been in use at least since the Middle Ages in Europe--and if they got the idea to use a bridge as the basis of a gantry crane, they probably could have gotten a lot bigger than they actually did! And cranes more generally go back to 1500 BC.
Unfortunately, according to Wikipedia "Crates had been used for many years without a clear origin in documented history. Modern crates from the early 20th century demonstrate a very evolved technology already considering practical and economic considerations built into crate designs." I can't imagine building a crate would really pose any problem for a Medieval carpenter, or even an ancient Mesopotamian one.
So, just how far back, and at what material technological level, would the development of something like the modern system of standardized container shipping have been possible to develop? (Say, if a time traveler went back and gave someone the idea.)