Which civilization first built engineered, standardized long distance roads: Persia, Rome, or an earlier network?
The Roman road network is the most famous engineered ancient road system and the one this atlas most often names by reflex, but it was neither the first nor necessarily the most extensive. The Persian Royal Road, built under the Achaemenid Empire and described by Herodotus, predates the major Roman roads by roughly two centuries and connected Sardis to Susa with a maintained relay postal system. Earlier still, evidence exists for engineered roadways in the Indus Valley Civilization and in Bronze Age Anatolia. Which of these counts as the first depends on how strictly the road must be engineered, standardized and centrally maintained rather than simply a well used route.
What would resolve this A settled archaeological and textual consensus on the earliest confirmed centrally engineered and maintained long distance road network, which current evidence does not yet provide with confidence beyond the Persian Royal Road as the earliest well documented case.
Archaeology, ancient historyWikipedia: Silk Road