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The Royal Persian Road was built between 550 and 486 BCE, by Cyrus II and Darius I, and was about 1500 miles long

It ran between Susa, Persia, and Saedes on the Aegean coast of modern Turkey. Its path likely followed an earlier track, dating to 3500 BCE.

Covering the entire route took 90 days, though royal post riders could travel it in 20, along a fully guarded route and post-stations a day's ride apart.

-- David Christian's "Big History", relying on Herodotus

https://en.wikipedia.org/wiki/Royal_Road