Arabarches is another name for Pompey--this Arabian chieftain.
In the early summer of this year Cicero returned to Rome, probably in time to see Atticus, who was then about to leave the city for his estates in Epirus.

We have a letter written by him to his friend on the journey, telling us that Caesar had made him two distinct offers, evidently with the view of getting rid of him, but in such a manner as would be gratifying to Cicero himself.[261] Caesar asks him to go with him to Gaul as his lieutenant, or, if that will not suit him, to accept a "free legation for the sake of paying a vow." This latter was a kind of job by which Roman Senators got themselves sent forth on their private travels with all the appanages of a Senator travelling on public business.

We have his argument as to both.

Elsewhere he objects to a "libera legatio" as being a job.[262] Here he only points out that, though it enforce his absence from Rome at a time disagreeable to him--just when his brother Quintus would return--it would not give him the protection which he needs.

Though he were travelling about the world as a Senator on some pretended embassy, he would still be open to the attacks of Clodius.