in a general sense, denotes any active power or cause. Agents are either natural or moral. Natural agents are such inanimate bodies as have a power power to act upon other bodies in a certain and determinate manner; as, gravity, fire, &c. Moral agents, on the contrary, are rational creatures, capable of regulating their actions by a certain rule.

Agent, is also used to denote a person intrusted with the management of an affair, whether belonging to a society, company, or private person.

Agents in rebus, one of the ranks of officers in the court of the Constantinopolitan emperors, whose business was to collect and convey the corn both for the army and household; to carry letters and messages from court to all parts of the empire; to regulate couriers, and their vehicles; to make frequent journeys and expeditions through the provinces, in order to inspect any motions, disturbances, or machinations tending that way, and to give early notice thereof to the emperor.

The agentes in rebus, are by some made synonymous with our post-masters, but their functions were of great extent. They correspond to what the Greeks call ἀποστόλοι, and the Latins veredarii.

There were various orders or degrees of agentes in rebus; as, tribunus, primicerius, senatus, ducentarius, biarchi, circitors, equites, tyriones, &c., through all which they rose gradatim. Their chief, who resided at Constantinople, was denominated princeps; which was a post of great dignity, being reckoned on a level with that of procurum. They were settled in every part of the empire; and are also said to have served as interpreters.