The Romans had a postal service in the second century that might be called "letter perfect." Nothing, or almost nothing, could keep their postal carriers from completing their rounds.
Known for the well-engineered roads that covered the empire, it was an easy task for their horse-drawn mail carts to travel in the second century at least 50 miles a day.
Relay teams, which could travel 50 miles a day and beyond, could easily deliver messages of urgency and were able to cover 170 miles a day.
Augustus and his successors used the so-called "cursus publicus" (fast course) mail course, which were reserved for government officials though private letters were usually carried by merchants and/or servants.