The Classical WorldTechnology Persian Royal Road c. 500 BCENotable A 2,700 km road with relay stations lets messengers cross the empire in about a week. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → Habitual fire and cooking → Homo sapiens appears → Complex language → Natufian villages → Oldest known bread → Agriculture begins → Irrigation → Uruk and the first cities → Cylinder seals → Writing (cuneiform) → Akkadian Empire → Neo-Assyrian Empire → Persian Empire founded → Persian Royal Road Community notesLoading notes… Learn more ranked by votesBookPierre BriantFrom Cyrus to Alexander: A History of the Persian Empire ↗Editor's pickVideoSearch on YouTubePersian Royal Road history ↗Editor's pick