Final answer:
Merchants often served as spies or informants for emperors, providing them with information on political and economic issues due to their access to different regions through trade. This role was a crucial aspect of maintaining an empire's security and was practiced across various historical periods, including Ancient Mesopotamia and during the times of the Mongol Empire.
Step-by-step explanation:
Other than trading their goods, another key role many merchants performed for the emperors was that of informants or spies who alerted the emperors to possible troubles. Given their constant travel and interactions with diverse groups, merchants could gather valuable intelligence. They provided updates on political developments, economic shifts, and public sentiment in regions both within and outside an empire's borders. Even in Ancient Mesopotamia, rulers like Hammurabi used spies to be informed of happenings in rival and friendly kingdoms. As narrated by the accounts of Marco Polo, merchants could carry intelligence and perform administrative duties in exchange for the right to trade. This practice of espionage was indeed risky; betrayal or getting caught could result in severe consequences.