In today's lecture, we'll discuss the history of the postal service. The first official postal system was established in Persia around 550 BC, using mounted couriers. However, it was the Romans who developed a more organized network, called the cursus publicus, for government messages. In the 19th century, the introduction of the postage stamp revolutionized communication. The first adhesive stamp, the Penny Black, was issued in Britain in 1840. Interestingly, it featured a portrait of Queen Victoria and was printed in black ink, hence its name. This innovation made prepayment possible and greatly reduced postal costs.