Marcus Anneius was legate

Legatus

A legatus was a general in the Roman army, equivalent to a modern general officer. Being of senatorial rank, his immediate superior was the dux, and he outranked all military tribunes...

 of Marcus Tullius Cicero

Cicero

Marcus Tullius Cicero , was a Roman philosopher, statesman, lawyer, political theorist, and Roman constitutionalist. He came from a wealthy municipal family of the equestrian order, and is widely considered one of Rome's greatest orators and prose stylists.He introduced the Romans to the chief...

 during his government in Cilicia

Cilicia

In antiquity, Cilicia was the south coastal region of Asia Minor, south of the central Anatolian plateau. It existed as a political entity from Hittite times into the Byzantine empire...

, in 51 BC.

Anneius appears to have had some pecuniary dealings with the inhabitants of Sardis

Sardis

Sardis or Sardes was an ancient city at the location of modern Sart in Turkey's Manisa Province...

, and Cicero gave him a letter of introduction to the propraetor

Promagistrate

A promagistrate is a person who acts in and with the authority and capacity of a magistrate, but without holding a magisterial office. A legal innovation of the Roman Republic, the promagistracy was invented in order to provide Rome with governors of overseas territories instead of having to elect...

 Quintus Minucius Thermus, that the latter might assist him in the matter.

In Cicero's campaign against the Parthia

Parthia

Parthia is a region of north-eastern Iran, best known for having been the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire....

ns in 50 BC, Anneius commanded part of the Roman troops.