Cicero's personal secretary and one of his closest confidantes, as well as the man to introduce shorthand to Latin, was a slave, although Cicero freed him well before his death. Plutarch mentions a slave of Pompey, a certain Demetrius, who had great influence over him and whom people approached to gain Pompey's favor. Plutarch claims that during the war of Actium Octavian set up an ambush against Antony on the advise of a slave. Again from Plutarch, we are told that Antony had a trusted personal slave, Eros, whom he ordered to kill him should it seem clear that he would fall into enemy hands--when the order was to be carried out Plutarch says that Eros turned the sword against himself instead.

I could go on listing examples of slaves as the confidantes and advisors of important Romans, but I don't see what the point would be. Household slaves, the only sort who would actually know their masters personally, were typically well-educated or trained in a skilled craft. They were used as secretaries, scribes, advisors, teachers, and other educated, skilled positions, while still being slaves and having no rights to their own bodies--the name of Antony's slave in Plutarch's account seems in part to suggest that the author is implying a sexual relationship between the two, although to my knowledge we have no other evidence for this person's existence. Such slaves might often expect to be freed, as Tiro was. Tiro, like many other such trained freedmen, continued to work for his former master, eventually helping to publish some of his works after his death. Likewise, house-slaves-turned-freedmen were an important source of skilled manpower for most men in the senatorial class, as they had been while they were still slaves. Ti. Gracchus supposedly used his own freedmen as apparitores, creating a core of very loyal support willing to engage in violence (as Plutarch relates it; Appian has no mention of the incident in question) and no doubt contributing to the feeling that Ti. was flying a little too close to the sun when it came to his own personal authority. Likewise, Shackleton Bailey in his prosopography showed that P. Clodius used as scriba during his tribunate a freedman called Sex. Cloelius. Bailey's reconstruction of his name is generally accepted today, but for a time the possibility that this freedman's name was Sex. Clodius, not Cloelius, was flying around, under the assumption that Clodius, like so many others of his rank, would have readily used his own freedmen on his staff.