For general-purpose communication, the gold standard for fast messaging was relay rider networks. Stations (or "posts") were set up at intervals along major routes where messengers (carrying written message or having memorized oral ones) could switch horses or even hand off the message to a fresh messenger (more practical for written messages than memorized ones, for obvious reasons). Since each horse would only be used for one short leg of the journey and would have plenty of time to rest between, messengers could ride at a speed that would otherwise exhaust or kill their horses. Herodotus reported such a system being used by the Achaemenid Persian Empire as early as the reign of Cyrus the Great (559–530 BC), describing it as having 111 stations along a major road (the "Royal Road" from the Winter Capital of Susa, through Mesopotamia and Anatolia through to Sardes on the Aegean coast) we know to be about 1700 miles (2700 km) long, which would make each leg of the journey about 15 miles. A messenger using the relay post system could cross the length of the road in about 9 days, compared to about 90 days for a small group traveling on foot.

Similar systems were used in India and China, by the Romans, by the Mongols, and probably by just about everyone else from Classical Antiquity onwards who had a chance to observe such a system in use and had a large enough empire for it to be worthwhile. The famous but short-lived Pony Express in the American West before the Civil War was a similar system and used pretty close to the same post spacing as the Achaemenid. The modern term "post" for mail services and messages sent thereby comes from the widespread use of relay posts for carrying mail.

For transmitting very urgent messages with a low level of information (for example, raising an alarm about a sudden attack at the border), signal beacons were also used. Think "The Beacons of Gondor" from Lord of the Rings: a series of large fires kept prepared but not lit and stationed on high places within sight of the next beacon in the chain in either direction. If you spotted flame or smoke from the next beacon, then you would set fire to your beacon as well, and so on up the chain. The Byzantine Empire set up a large beacon system across Anatolia in the 9th century AD, and smaller local beacon systems were used in several places in Europe in the early middle ages. These could carry a message much faster than messengers (the Byzantine system could have sent a message ~450 miles in about an hour), but they had the big disadvantage of having far lower bandwidth: usually one bit of information, whether the beacon is lit or not, although the Byzantines also had a system where the meaning of the beacons changed depending of the time of day. A post relay system, on the other hand, could carry dozens or hundreds of pages of messages per messenger, with several messengers traveling in either direction at any particular time. Both systems were expensive, but the broader utility of the post relay system lead to it being used far more often than beacons.