In which country was the first mail invented?

The first mail was invented about 5 thousand years ago in Mesopotamia. Around the 3rd millennium BC. the Assyrians had the first semblance of a written envelope. When a clay tablet with the text was fired, clay was applied on top and the recipient’s address was written on it. Sometimes carrier pigeons were used to deliver letters. In Persia, there was a relay mail, letters were passed from one messenger to another. In ancient Rome, letters were delivered by horse couriers. In Greece, despite the existence of sea and land postal communications, the delivery of letters with the help of runners became widespread, they covered about 10 km in one hour.