  However, one of the great themes of the Persian Letters is the virtual impossibility of self-knowledge, and Usbek is its most fully realized illustration. Usbek has left behind a harem in Persia, in which his wives are kept prisoner by eunuchs who are among his slaves. Both his wives and his slaves can be beaten, mutilated, or killed at his command, as can any outsider unfortunate enough to lay eyes on them. Usbek is, in other words, a despot in his home. From the outset he is tortured by the thought of his wives' infidelity. It is not, he writes, that he loves his wives, but that "from my very lack of feeling has come a secret jealousy which is devouring me" (Letter 6). As time goes on problems develop in the seraglio: Usbek's wives feud with each other, and the eunuchs find it increasingly difficult to keep order. Eventually discipline breaks down altogether; the Chief Eunuch reports this to Usbek and then abruptly dies. His replacement is clearly obedient not to Usbek but to his wives: he contrives not to receive any of Usbek's letters, and when a young man is found in the seraglio he writes: "I got up, examined the matter, and found that it was a vision" (Letter 149). Usbek orders another eunuch to restore order: "leave pity and tenderness behind. ... Make my seraglio what it was when I left it; but begin by expiation: exterminate the criminals, and strike dread into those who contemplated becoming so. There is nothing that you cannot hope to receive from your master for such an outstanding service" (Letter 153). His orders are obeyed, and "horror, darkness, and dread rule the seraglio" (Letter 156). Finally, Roxana, Usbek's favorite wife and the only one whose virtue he trusted, is found with another man; her lover is killed, and she commits suicide after writing Usbek a scathing letter in which she asks: "How could you have thought me credulous enough to imagine that I was in the world only in order to worship your caprices? that while you allowed yourself everything, you had the right to thwart all my desires? No: I may have lived in servitude, but I have always been free. I have amended your laws according to the laws of nature, and my mind has always remained independent" (Letter 161). With this letter the novel ends.