Dr. Lowth says, that grammar requires us to say, Whom do you think me to be. But in conversation we always hear Who do yo think me to be. It is invariable practice to use who , except among people who are fettered by grammatical rules. I do not think, however, that the construction is generally pleasing. This want was supplied in the common periphrastic manner, by the help of the preposition and the article.
Some grammarians remonstrate.
But it ought to be remembered, that use well established must give law to grammar, and not grammar to use. Nor is this acceptation of the word whose of recent introduction into the language. It occurs even in Shakespeare, and almost uniformly in authors of any chanracter since. Which, whose and that refer to things and persons. Essay on Dram.