The 93rd discusses the death of Louis XIV, and is written by Usbek, one of the two main authors along with Rica.  
The last of them begins "YES, I have deceived you; I have led away your eunuchs; I have made sport of your jealousy," and is written by Roxana.  The 14th includes a discussion of the Troglodites, and the 81st famously includes the author's theories on government.  Several were written in Tauris and the Seraglio at Ispahan.  The 93rd discusses the death of Louis XIV, and is written by Usbek, one of the two main authors along with Rica.  Published anonymously in 1721, FTP, name this series of 161 fictitious epistles, purported to be written by various Arabs, but actually written by Montesquieu.
The last of them begins "YES, I have deceived you; I have led away your eunuchs; I have made sport of your jealousy," and is written by Roxana.  
Persian Letters or Les letters persanes