As technology is growing, we are able to communicate with others through the Internet and get a respond in no time. Therefore, we human take it for granted. However, have you ever wonder how long distance communication occurs centuries ago when technology was not advanced in those days?
From 200 BC to 100 BC, it is a common phenomenon to see human messagers on foot or horseback delivering a message in Egypt (Second Millennium BC) and China (First Millennium BC). Human messagers in those days went through a lot of difficulties and have risked their life just to deliver a message to the recipient (Point-to-point communication). Message relay stations were placed along major roads so that human messagers could travel from one station to another. In China, fire pits which acted as relay station were set up along the Great Wall of China to signal the enemies’ attacks.
During the Roman relay system in 14AD, human messagers ran through 80km per day for regular mail and 160 km per day for express mail. In 490 BC, Phidippides ran from Marathon to Athens just to warn the Athenians of an approaching Persian army and unfortunately, he died of strain. Besides that, in Kublai Khan, riders covered 200 t0 250 miles per day to deliver a message and 300 miles per day for extreme circumstances. They changed horses in relay station and signal their coming through horns.
In those days, messages could be written in secret writing (Cryptography) which was constructed from symbols that can represent a complete message. Besides that, secret writing was also used to construct an arbitrary message. Message could be encoded using cryptography, a process called encryption if the messages are to be kept secret. For instance,
A simple transposition code:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
h j l q g x k a o u d c t p i v b z r m w f y e s n
§ MAOY OY YXLSXM
This is secret
Besides human messagers, there were also ways to send a message in those days. For example, a message could be send via smoke signals as well as through well trained pigeon and mirrors to reflect light. However, this technique was used especially in desert where there is lot of sunlight. In my opinion, it is not a wise decision to send a secret message via smoke signals because certain patterns of puffs could be decoded by the enemy without oneself realizing it.
Posted by E-hua