Milestones in mail delivery.
In ancient Persia, message carriers called chapars galloped from one post to the next, hopping onto a fresh horse to continue their delivery. The historian Herodotus described the chapars
in words that sound familiar 2,500 years later: The carriers were "stayed neither by snow nor rain nor heat nor darkness from accomplishing their appointed course with all speed."
Established in the sixth century BC, the Persian postal system -- which doubled as a spy network -- was arguably the world's first. (But earlier pharaohs in Egypt had employed a courier system for their decrees.) Inspired by the Persians, the Romans started mail delivery under Augustus Caesar. His cursus publicus (Latin for "public road") was originally intended only for official messages, but eventually the relay system broadened to mail and what would later be known as parcel post.
Later European systems employed everything from homing pigeons to traveling monks. Holy Roman Emperor Maximilian I established a postal system in 1505 that outlasted the empire itself, finally being absorbed into the German mail service after 1871.