" 
 :""May have succeeded"" is simply wrong. It conveys a different meaning (we do not know whether or not he succeeded) than ""might have succeeded"" (perhaps possibly at the time, but contrary to what did actually happen). I just fixed it in the article. The ongoing change in English is an enormous topic; is there an existing article on it? With some quick looking I found Modern English and History of English which don't really do it justice. __   "