"By the eighth century B.C., Greeks were using pigeons to send the results of Olympic Games from town to town. Genghis Khan used pigeons to create a communication network across his empire in 12th century A.D." (http://www.nytimes.com/2013/02/05/science/pigeons-a-darwin-favorite-carry-new-clues-to-evolution.html?hpw, accessed 02-04-2012).
"The story of Noah in the Bible describes one of the earliest uses of the pigeon as a messenger. Noah sent the pigeon from the ark to see if the deluge was over. It was sent a few times before it came back with a branch of an olive tree in its beak, which proved to Noah that the waters had begun to subside. There are even earlier writings, such as the Sumerian ‘Epic of Gilgamesh’, that also include a story about a great flood and how a pigeon played the role of a messenger.
"Tablets, found in Mesopotamia (areas around Iraq and Iran of today), as well as Egyptian hieroglyphics, suggest that pigeons were being domesticated by both civilizations already around 3000 BCE. Eventually, in time, they learned how to use their homing instincts for communication purposes. For example the Egyptians would release pigeons in order to announce, to the people, the rise of a new pharaoh.
"There are records that indicate that Phoenician merchants used to take pigeons on their ships during their business trips in the Mediterranean and would let them go whenever they needed to release information about their business tours.
"The Greeks used carrier pigeons to release the results of the Olympic games and to send messages about victories in their battle fields.
"Frontinus, the Roman writer, tells about the use of carrier pigeons by Julius Caesar. There are documents about the existence of columbarium in Rome that contained over 5000 pigeons.
"Conquerors throughout history, such as Hannibal and Genghis Khan, also used pigeon-post as a communication network.
"The added value for using pigeons as message carriers in the ancient world was quite significant.
"When compared to other means of long distance communication in ancient times, such as smoke, drums and human messengers, pigeon carriers provided a more private and discrete way of transferring messages" (https://wysinfo.com/doves-and-pigeons-in-history/)