Who is Solim from Persian Letters. Translated with an Introd. and Notes, by C. J. Betts and what is their importance?

Solim is a black slave. He writes to Usbek informing him that he was with the head eunuch when he died and that he was instructed to tell Usbek what was happening in the seraglio. Solim tells Usbek what he has observed, and he also provides him with his opinion that Narsit, the oldest black slave, isn't intelligent enough to govern the seraglio properly. As a result, Usbek determines that Solim should take over as head eunuch.